NSCA has the CSCS and CPT certification. I think the NSCA-CPT deals more with "core and functional" than the CSCS. The CSCS handles more athletic settings and training conditions conducive to performance. NASM is of a joint-to-joint approach to training relying heavily on their OPT model (which you are probably referring to as functional).
There may be some threads on here that we discuss the pro's and con's of each organization that may be helpful. You may want to do a "advanced search" on here or maybe someone will pop in to guide you. You can always visit the
NSCA website and find out what the curriculum for each cert entails.