This is a reference guide that I wrote in late 2007, and then posted on VFXTalk in about November of that year. As such, it's more based around Nuke 4.8, and I'm sure there's a good amount that probably should be updated.

It is all, obviously, only my opinion, and it was also written by me at a time when I had very little Nuke experience...

For now, though, I just wanted to put it up on here as-is, and then I'll go through updating it as things crop up.

Any Nuke node that begins with "N_" is part of the NFX Plugins bundle which is a free external plugin suite. The dFielder gives Nuke the functionality to deal with interlaced footage.

Any Nuke node that begins with "F_" is part of FurnaceCore, and comes with NukeX

• (+) Means that Nuke's is better
• (-) Means that Nuke's is worse
• (=) Means that Nuke's is the same
• (?) Means that I've not used it enough (in one or other package) to make a reasonable comparison
• (~) Means that Nuke's is different
• (X) Means that Nuke, as far as I am aware, doesn't have it or a direct equivalent

Image

• Checker -> Checkerboard (+)
• Color -> Constant (=)
• ColorWheel -> ColorWheel (=)
• FileIn -> Read (=)
• FileOut -> Write (=)
• Grad (X) Could be recreated with a couple of Ramp nodes and some grading
• QuickPaint -> Paint (-)
• QuickShape -> Bezier (+)
• Ramp -> Ramp (+)
• Rand -> N_Rand (+)
• RGrad -> Radial (-)
• RotoShape -> Bezier (-)
• Text -> N_Text (+)

Color

• Add -> N_Add (=)AdjustHSV -> HSVTool (?)
• Brightness -> Multiply (=)
• Clamp -> N_Clamp (+)
• ColorCorrect -> ColorCorrect (?)
• ColorMatch (X)
• ColorReplace (X)
• ColorSpace -> ColorSpace (+)
• ColorX -> Expression (=)
• Compress -> N_Compress (=)
• ContrastLum (X) Can be recreated by converting to HLS (with ColorSpace) and doing a normal Contrast
• ContrastRGB -> RolloffContrast (+)
• Expand -> N_Expand (=)
• Fade -> Multiply (=)
• Gamma -> Gamma (-)
• HueCurves -> HueCorrect (?)
• Invert -> Invert (=)
• LogLin -> Log2Lin (=)
• Lookup -> Lookup (=)
• LookupFile -> Lookup (=)
• LookupHLS (X) Recreate by converting to HLS with a ColorSpace and doing a Lookup
• LookupHSV (X) Recreate by converting to HSV with a ColorSpace and doing a Lookup
• MDiv -> Unpremult (=)
• MMult -> Premult (=)
• Monochrome -> N_MonoChrome (=)
• Mult -> N_Mult (=)
• Reorder -> Shuffle (+)
• Saturation -> Saturation (+)
• Set (X) Do with Remove (the wanted channel(s)) then Add the same channel(s) with the right value
• SetAlpha (X) As Set
• SetBGColor (X)
• Solarize (X)A Lookup going (0,0 -> 1,0.5 -> 0,1) - move the middle point left and right.
• Threshold (X)
• Truelight -> Truelight (=)
• VideoSafe (X)

Filter

• ApplyFilter (X)
• Blur -> Blur (+)
• Convolve -> Convolve (~)
• Defocus -> Defocus (+)
• DilateErode -> Erode (fast/filter/blur) (?)
• EdgeDetect -> EdgeDetect (=)
• Emboss -> Emboss (?)
• FilmGrain -> Film Grain Simulation (?)
• Grain -> Film Grain Simulation (?)
• IBlur (X) Could probably be faked with ZBlur
• IDefocus (X) Could probably be faked with ZDefocus
• IDilateErode (X)
• IRBlur (X)
• ISharpen (X)
• Median -> Median (+)
• PercentBlur -> Blur (+)
• Pixelize -> Blocky (=) Blocky isn't in the main menus, but can be found under "Other -> All Plugins -> B" (need to press "update menu"). This may be because it's buggy.
• RBlur -> GodRays (~)
• Sharpen -> Sharpen (+)
• ZBlur -> ZBlur (?)
• ZDefocus -> ZDefocus (?) The ZDefocus node isn't in the main menus, but can be found under "Other -> All Plugins -> Z" (need to press "update menu"). This may be because it's buggy.

Key

• ChromaKey -> HueKeyer (=)
• DepthKey -> Keyer (?) Luminance Key with the Input set to Depth
• DepthSlice -> ZSlice (-)
• LumaKey -> Keyer (-)
• Primatte -> Primatte (=)
• SpillSuppress -> HueCorrect (~)
• Keylight -> IBK (~) Different, but much nicer!

Layer

• AddMix -> AddMix (=)
• AddText -> N_Text (+)
• Atop -> Merge (atop) (=)
• Common (X)
• Constraint (X)
• Copy -> Copy (+)
• IAdd -> Merge (plus) (=)
• IDiv -> Merge (divide) (=)
• IMult -> Merge (multiply) (-) If both A < 0 and B < 0 then the result is 0 instead of >0. A Shake-style IMult can be done with the expression node, or by multiplying both inputs by -1, doing a Merge (multiply) and the Maxing the result with the original result.
• Inside -> Merge (in) (=)
• Interlace (X)
• ISub -> Merge (minus) (=)
• ISubA -> Merge (difference) (=)
• KeyMix -> Keymix (=)
• LayerX -> MergeExpression (=)
• Max -> Merge (max) (=)
• Min -> Merge (min) (=)
• Mix -> Dissolve (=)
• MultiLayer -> Merge (-)
• MultiPlane -> 3D System (+++)
• Outside -> Merge (out) (=)
• Over -> Merge (over) (=)
• Screen -> Merge (screen) (=)
• SwitchMatte -> Copy (-) (A and B are swapped, and doesn't premult)
• Under -> Merge (under) (=)
• Xor -> Merge (xor) (=)
• ZCompose -> ZMerge (=)

Transform

• AutoAlign -> F_Align (?)
• CameraShake -> CameraShake (+)
• CornerPin -> CornerPin (+)
• Crop -> Crop (=) with "reformat" on
• Fit -> Reformat (~)
• Flip -> Mirror (=)
• Flop -> Mirror (=)
• MatchMove (X)
• Move2D -> Transform (-)
• Move3D -> Card3D (+)
• Orient (X)
• Pan -> Position (=)
• Resize -> Reformat (~)
• Rotate -> Transform (+)
• Scale -> Transform (+)
• Scroll -> Transform (+)
• SetDOD -> Crop (=) with "reformat" off
• Shear -> Transform (-) Only does X shear (skew)
• Stabilize -> Tracker (+)
• SmoothCam -> F_Steadiness (~)
• Tracker -> Tracker (~)
• Viewport -> Reformat (~) with "resize type" on "none"
• Window -> Crop (=)
• Zoom -> Reformat (+)

Warp

• DisplaceX (X) Although STMap does UV texturing
• IDisplace -> IDistort (=)
• LensWarp -> PerspDistort (-)
• Morpher (X)
• PinCushion (X)
• Randomize -> N_Scatter (+)
• Turbulate (X) Workaround with N_Rand, scaled up (Transform) then the R and H channels copied into forward.u and forward.v of the image to turbulate. Then use an IDistort node.
• Twirl -> Twist (?) Twist isn't in the main menus, but can be found under "Other -> All Plugins -> T" (need to press "update menu"). This may be because it's buggy. You need to up the "Mesh Density" otherwise it'll just look like it's rotating.
• Warper -> SplineWarp (+) with "mapping" on
• WarpX (X)

Other

• AddBorders (X)
• AddShadow (X) But so easily doable by hand
• Bytes (X) Unneeded - everything is float internally
• Cache -> DiskCache (+)
• DeInterlace (X)
• DropShadow (X) See AddShadow
• Field (X)
• Histogram -> Histogram (~) More like PhotoShop's "Levels"
• PixelAnalyzer -> CurveTool (+)
• PlotScanline -> Sampler (~) Shows it as a curve rather than drawing on screen
• Select -> Switch (=)
• SwapFields (X)
• Tile -> Tile (=)
• TimeX -> TimeWarp (+) or any of the other Time nodes. Anything's better than Shake's TimX
• TLCalibrate (X)
• Transition -> AppendClip (~)