It all depends on what year your truck is.
If you have a Gen1 then Total Chaos Fabrication makes a kit. If you have a Gen2 (2005 and up) there are a few ways to do it. You can build your own by just adding Titan front suspension parts on to your Frontier. PRG also has a kit with coilovers, control arms and axles.
2005 NISMO CC 4X4-ICON 2.5 coilovers,AC 3 leaf pack,Bilstein shocks, 3" Body lift, Titan front differential, Pathfinder half shafts, 305/70R16, American Outlaw Colt wheels, KMA rear bumper, Black Widow Off Road hi-lift mount, Home made utilitrac spare tire mount, Airflow snorkel, Shrockworks sliders and skids