I use a standard four finger power grip but my index finger does not seem to be gripping the disc as hard as the other three...would this be why i am having some nose-up issues along with not enough snap

I used to have that problem as well, I now use a 3 finger grip, but that's also because my pinky is abnormally smaller than the others, so I would focus more on that finger. Now i've got snap and grip strength but still lack distance

not sure if it explains the nose up issues but is likely one of the causes of the lack of snap.

you can consult this article for more answers
http://www.discgolfreview.com/resources/articles/gripittoripit.shtml

What grip would you suggest for someone having the problem?
I think I have the same problem...I just can't get the fingertip around the rim to feel comfortable and strong.

Are you able to get long distance with the bonapane grip? i began to use this grip earlier and achieved low, straight drives but not very far.....

I'd been having too many nose up problems, and keeping my wrist down enough to keep it nose down was difficult, inconsistent and uncomfortable.

One day I looked at my hands. I noticed that my middle finger is quite a bit longer than my index finger. So I got a disc, and gripped it. My middle finger was pushing up on the flight plate, while my index was barely on the rim. So I moved my middle finger off the rim.... I tried the birdie grip with it out on the flight plate but that didn't feel comfortable. So I stacked the middle finger over the ring finger. This increased the lock strength of my grip, took the middle finger off the flight plate making a more natural nose down grip, and allowed a better and stronger grip and rip from my index finger.

I'd been playing for three years, and it had never occurred to me to try a stacked grip before... now, I'll never go back.

Moral: try things out!!!!!!

you may not be extending your arm out in front of you on your release. Your best bet is to try and throw your arm out of socket. sort of