Both Katzkin and Classic Trim have leather kits for the Nitro...
I priced out a Katzkin interior with two tone and perforation in the inserts and embroidered R/T logo installed for around 1000 to 1100. You figure the factory leather is $770.00. Is an extra $300 or so worth the 'custom' look. I personally think so... thats why I got the cloth in my R/T so I could get exactly what I wanted in my leather...
A couple of other great members here turned me on to Classic Soft Trim as another option. They do alot of the dealership aftermarket leather installs so they are familiar with the product as is Katzkin. Below are some links... I hope this helps out a bit.
Katzkin Leather
Classic Soft Trim
-Lil