Hi just bought a new Nickle shotgun that is totally covered in grease including the stock. Would goo b gone be ok for wiping the gun down and not hurt the finish or any better ideas out there

On my mosin I just wiped cosmoline off with a soft paper towel. After that cleaned it once. Then cleaned agian and oiled. Probably overkill but.

I don't think I would use that stuff. Wipe as much off as possible with an old tee shirt or something similar. I've used lighter fluid on a rag as a solvent for grease. Outside, away from any potential source of ignition.

Rubbing alcohol works great for cutting grease. Not sure about using on a stock though...
I’d think the previous suggestions of a soft rag or paper towels would be a safer bet on the wood.

Take the wood off. Wrap it in newsprint and put it in a black garbage bag wrapped up. Set it the sunlight, even in a window that gets direct sun so that it gets hot. Change out the paper as it soaks it up. Takes time but it works to suck the grease out of the wood. Solvents just get it in deeper. Easy Off oven cleaner as a last ditch. Be prepared it if is really greased up the wood will weep oil from the grease every time it gets hot pretty much forever in bad cases. If it's relatively new it shouldn't be as bad.

The metal parts, clean with mineral spirits and a brush. Probably want to do that outside and wear some thick nitrile gloves. Don't use gasoline, none of your neighbors care to see a gasoline doused flaming spastic running about the neighborhood.

nickel as in nickel plated?
what type of stock, wood? synthetic?

if nickeled and syn, just get some hoppes, mineral spirits, or gentle solvent and get to wiping,

if wood stock, would depend on the type finish