upgraded my Nexus from 14.3 to 15.2 last night. supersu was upgraded as mentioned on page 2605 of this post ... problem comes when without me knowing, Google Play upgraded supersu to the latest version and during its install the phone rebooted and since has been locked on the Google splash screen
would appreciate any help as to how to fix this problem
I believe I was the one who had a similar issue going from a 14 to 15.2 and being stuck at the Google logo. I ended up doing a reset to stock before I did anything else with the phone because it was acting so oddly.
I think that the actual cause is outdated root binaries. Re-root with the latest supersu.zip from TWRP or CWM and then see if it'll boot? If not, you may need to wipe, reroot, then reflash 15.2.