First, this forum is for the tower Mac Pro system. The MacBook Pro forum can be found here:
MacBook Pro
Anyway, Windows programs do not natively run on Macs. You may be able to get Nitro to run, though either via Boot Camp or one of the virtualization solutions, such as Parallels Desktop, VMWare Fusion, or VirtualBox, that allow you to run a "guest" OS under Mac OS X. You'll need to confirm whether Nitro will run in such circumstances, and if it will, you'll need a copy of Windows. Whether you choose the 32-bit or 64-bit version of Nitro will depend on what release of Windows you choose, or can, run. I'd suggest asking for advice in the Nitro forums, if the developer provides customer forums.
Regards.