There is the product you need!I just put my head unit in my '07.
I went with the Metra kit. Part # 99-7603. I don't remember if that is the same for 2012, but you can check which fits your 2012 on their site. The other place that would make a dash kit would be Scosche.
When I found that part I needed I searched on Amazon, ebay, etc. till I found a good price.
You will also need the wiring harness, and antenna adapter, both companies make those as well.
You want a 2 or 4 speaker system? Try Crutchfield Car Selector They can sell you all the hardware including radio's, speakers, dash kits etc. They have a good and knowledgeable sales dept. Give them a call if you can't find what your looking for.Where do i buy a Kit to Install A radio for my nissan versa 2012 sedan? and does anyone know to to install it?