If you are using the stock 8.2 inch rear, you can put in pretty much any gear ratio you want, but the carrier might not be the right one for the gear. Different carriers are made for different gears. Most of the 8.2 inch rears came with 2 something gears up to the low 3 somethings. While you are doing this, it would be a good time to put in a posi unit, then you can get the carrier to fit whichever gear you go with and get both rear wheels spinning instead of just one.
About the nitrous, the 10 bolt rear can take some power but maybe not as much as you are planning on putting through it.
As far as gear ratios, 3.73 are a little low (numerically high) if you are going to do mainly highway cruising. They are a good accelleration gear, but you will be pushing around 3000rpm at 65mph with 26.5 inch tires. A good compromise would be something closer to 3.31-3.42. It really all depends on what you are willing to put up with though.