Creates a Chromatic Aberration in Nuke. It utilizes the LensDistortion node to scale the color channels stronger around the edges. There is also an option to blur the distortion for each channel.

CS_ChromaticAberration.tcl

set cut_paste_input [stack 0]
version 10.5 v3
push $cut_paste_input
Group {
 name CS_ChromaticAberration1
 tile_color 0xcc804eff
 addUserKnob {20 CS_ChromaticAberration}
 addUserKnob {20 Red_Cyan l Red/Cyan n 1}
 addUserKnob {41 distortion1_red l "Radial Distortion 1" T LensDistortionRed.distortion1}
 addUserKnob {41 distortion2_red l "Radial Distortion 2" T LensDistortionRed.distortion2}
 addUserKnob {41 distortionCenter_red l "Distortion Center" T LensDistortionRed.distortionCenter}
 addUserKnob {41 scale_red l blur T VectorBlur2_1.scale}
 addUserKnob {41 mix_red l mix T CopyRed.mix}
 addUserKnob {20 endGroup_red l endGroup n -1}
 addUserKnob {20 Green_Magenta l Green/Magenta n 1}
 addUserKnob {41 distortion1_green l "Radial Distortion 1" T LensDistortionGreen.distortion1}
 addUserKnob {41 distortion2_green l "Radial Distortion 2" T LensDistortionGreen.distortion2}
 addUserKnob {41 distortionCenter_green l "Distortion Center" T LensDistortionGreen.distortionCenter}
 addUserKnob {41 scale_green l blur T VectorBlur2_2.scale}
 addUserKnob {41 mix_green l mix T CopyGreen.mix}
 addUserKnob {20 endGroup_green l endGroup n -1}
 addUserKnob {20 Blue_Yellow l Blue/Yellow n 1}
 addUserKnob {41 distortion1_blue l "Radial Distortion 1" T LensDistortionBlue.distortion1}
 addUserKnob {41 distortion2_blue l "Radial Distortion 2" T LensDistortionBlue.distortion2}
 addUserKnob {41 distortionCenter_blue l "Distortion Center" T LensDistortionBlue.distortionCenter}
 addUserKnob {41 scale_blue l blur T VectorBlur2_3.scale}
 addUserKnob {41 mix_blue l mix T CopyBlue.mix}
 addUserKnob {20 endGroup_blue l endGroup n -1}
 addUserKnob {26 ""}
 addUserKnob {26 Creator l "" +STARTLINE T "CS_ChromaticAberration v1.2 by Christian Schulze - www.christian-schulze.eu"}
}
 Input {
  inputs 0
  name Input
  xpos -40
  ypos -274
 }
 Dot {
  name Dot13
  xpos -6
  ypos -198
 }
set N6cb6400 [stack 0]
 Expression {
  channel0 {forward.u -forward.v}
  expr0 x
  channel1 {-forward.u forward.v}
  expr1 y
  channel2 none
  name Expression1
  xpos -150
  ypos -202
 }
 Dot {
  name Dot18
  xpos -226
  ypos -198
 }
set N6cb7800 [stack 0]
 Dot {
  name Dot5
  xpos -336
  ypos -198
 }
set N6cb7400 [stack 0]
 Dot {
  name Dot12
  xpos -556
  ypos -198
 }
set N6cf1800 [stack 0]
 Dot {
  name Dot3
  xpos -666
  ypos -198
 }
set N6cf1400 [stack 0]
 Dot {
  name Dot8
  xpos -886
  ypos -198
 }
set N6cf1000 [stack 0]
 Dot {
  name Dot2
  xpos -996
  ypos -198
 }
 Dot {
  name Dot7
  xpos -996
  ypos -54
 }
push $N6cf1000
 LensDistortion1_0 {
  serializeKnob ""
  serialiseKnob "22 serialization::archive 9 0 0 0 0 0 0 0 0 0 0 0 0"
  distortion1 0.01
  cardScale {1.010204911 1.010204911 1}
  a -0.001685338444
  b -0.006407799199
  c -0.002735857619
  name LensDistortionRed
  xpos -920
  ypos -130
 }
 Merge2 {
  inputs 2
  operation minus
  Achannels forward
  Bchannels forward
  output forward
  name Merge1
  xpos -920
  ypos -64
 }
 VectorBlur2 {
  channels rgba
  uv forward
  scale 1
  name VectorBlur2_1
  xpos -920
  ypos 8
 }
 Dot {
  name Dot6
  xpos -886
  ypos 186
 }
push $N6cf1400
 Dot {
  name Dot11
  xpos -666
  ypos -54
 }
push $N6cf1800
 LensDistortion1_0 {
  serializeKnob ""
  serialiseKnob "22 serialization::archive 9 0 0 0 0 0 0 0 0 0 0 0 0"
  name LensDistortionGreen
  xpos -590
  ypos -130
 }
 Merge2 {
  inputs 2
  operation minus
  Achannels forward
  Bchannels forward
  output forward
  name Merge2
  xpos -590
  ypos -64
 }
 VectorBlur2 {
  channels rgba
  uv forward
  name VectorBlur2_2
  xpos -590
  ypos 8
 }
 Dot {
  name Dot1
  xpos -556
  ypos 138
 }
push $N6cb7400
 Dot {
  name Dot16
  xpos -336
  ypos -54
 }
push $N6cb7800
 LensDistortion1_0 {
  serializeKnob ""
  serialiseKnob "22 serialization::archive 9 0 0 0 0 0 0 0 0 0 0 0 0"
  asymmetricDistortion {-0.005 0}
  name LensDistortionBlue
  xpos -260
  ypos -130
 }
 Merge2 {
  inputs 2
  operation minus
  Achannels forward
  Bchannels forward
  output forward
  name Merge3
  xpos -260
  ypos -64
 }
 VectorBlur2 {
  channels rgba
  uv forward
  name VectorBlur2_3
  xpos -260
  ypos 8
 }
 Dot {
  name Dot4
  xpos -226
  ypos 90
 }
push $N6cb6400
 Copy {
  inputs 2
  from0 rgba.blue
  to0 rgba.blue
  name CopyBlue
  xpos -40
  ypos 80
 }
 Copy {
  inputs 2
  from0 rgba.green
  to0 rgba.green
  name CopyGreen
  xpos -40
  ypos 128
 }
 Copy {
  inputs 2
  from0 rgba.red
  to0 rgba.red
  name CopyRed
  xpos -40
  ypos 176
 }
 Output {
  name Output
  xpos -40
  ypos 278
 }
end_group