This should work:

1. create a multMatrix node
2. connect the camera.worldMatrix to multMatrix.matrixIn[ 0 ]
3. connect your object.worldInverseMatrix to multMatrix.matrixIn[ 1 ]
4. create a pointMatrixMult node and a samplerInfo node
5. connect the multMatrix.matrixSum to pointMatrixMult.inMatrix
6. connect the samplerInfo.normalCamera to pointMatrixMult.inPoint
7. set pointMatrixMult.vectorMultiply on
8. create a surfaceShader
9. connect pointMatrixMult.output to the surfaceShader.outColor attribute
10. attach the shader

It might not look right in the viewport, but when you render you should see that where the surface normal is facing the object's local X it will be red, local Y will be green, local Z will be blue. It will work where ever you put the camera or the object.

If you want the RGB aligned to XYZ world space, just plug the camera worldMatrix straight into the pointMatrixMult node.

The normals in negative XYZ will have negative RGB values, so you probably want to normalize the colors. You can make an expression:

surfaceShader1.outColorR = ((pointMatrixMult.outputX * 0.5) + 0.5);

and the same for green and blue...