There are no SNAP functions for working with CDFs. In fact, the SNAP approach is to *hide* any dependence on CDFs. You specify Windows colors, like "Red" or "Green", and then SNAP figures out internally what color table indices to use to get the requested colors. That way, you get the colors you asked for even if the CDF changes.
But, as always, there is no reason that your code can't mix calls to NX/Open functions and calls to SNAP functions. I do this all the time, myself -- I call SNAP functions when they're available (because they're easier to underdstand and use), and call NX/Open functions when I need to (like in this case).
I think the appropriate NX/Open function is NXOpen.UF.UFDisp.LoadColorTable, but I'm not 100% sure.