In your situation, I would not use nails to repair the loose bannister. I would pull back the carpet a bit, and look at the fit between the bannister and the landing. It might be possible to inject an epoxy paste where the two parts are joined. When the glue has cured, the bannister should be secure.

seen this on the HGTV show Don't Sweat it

Here is a link that might be useful: fix a loose banister

I've looked at the banister again which is at the top of the steps. My mom grabs hold of it to pull herself up and I think this is why its becoming loose. The main post is what's real wiggly and the post that goes into the wall is also wiggly.

I will remove the carpet to see what's going with the bottom post. Any ideas on how to secure the post that's in the wall?

Thanks for the help.

Peaches

There are any number of ways your newel post/railing may be fastened, and each could have a particular remedy; until you get to the heart of the problem, we are limited in the accuracy of the advice we can give. In any case, nails will be of no help whatsoever. You must pull back the carpet to determine what's gone wrong with the original fastening method.
Casey

Many banisters are held together with draw bolts. When they become loose, it is very simple to fix.

Wherever there is a loose joint, look around the adjoining pieces for a small round wooden plug. (about the size of a dime or nickel, depending on the size of the bolt) In your case, look around the base of the post. There may be a draw bolt holding it to the floor.

Simply pry out the plug being careful not mar the wood too badly, then insert the proper size socket and tighten.

Replace the plug.

Here is a link that might be useful: Other home repair tips