Some posts exist on this populse_sandbox issue (populse/populse_sandbox#23).
To sum up:
The goal is to use Matlab/SPM scripts standalone or not, for the same pipeline and with ease.
Go further with environment variables with Nipype: Define FORCE_SPMMCR & SPMMCRCMD just before running. In order to pass easily from Matlab/SPM to MCR/SPM Standalone
For Matlab/SPM (non-standalone), the spm12 path NEEDS to be in the MATLABPATH environment variable
This is a copy of populse/populse_sandbox#23. Do not forget to close concomitantly the populse/populsesandbox#23 and this issue !
M40V
commented
5 years ago 
Some posts exist on this populse_sandbox issue (populse/populse_sandbox#23). To sum up:
This is a copy of populse/populse_sandbox#23. Do not forget to close concomitantly the populse/populsesandbox#23 and this issue !