how to get more horsepower out of my 2011 frotier 4.0liter

First of all, don't waste your money on those "performance chips" that sell for $59 - $129 -- what you'll find is that these wire into your vehicle's IAT sensor circuit and will "fool" your ECM into thinking that the intake air is colder than it actually is -- the response is then to add more fuel to the MAP which SOUNDS like it would equal more power but, instead will cause NO performance increase, lower fuel mileage and cause a multitude of other problems ( fouled plugs, restricted catalytic converter, O2 sensor damage, etc. ). If you want a performance chip, stick with reputable brands like "Bully Dog", "Jet" and "SuperChips". Yes, they are considerably more expensive but, they work and are backed by their individual warranty. For less expensive performance increases, changing to a K&N intake and swapping your belt driven engine fan to an electric fan ( which will reduce engine drag ) will give you small but noticeable performance and MPG increases.

Nismo cold air intake, Magnaflow cat back exhaust,and a cheap performance chip does work with these mods quite well. Tried without chip couldn't stand the power loss. Cheap chip may not work in stock form.