Really to get a nuke all you need to do is stay concentrated on yor goal ... once youve got your harriers youve pretty much got your nuke. Once youve got your harriers call them in a place were you are safe surrounded by your team mates. If you get your chopper gunner whilst your harrier is still in the air, dont use it straight away let your harriers get a couple of kills.
KILLSTREAK:
7 KILL STREAK - HARRIER AIRSTRIKE
11 KILLSTREAK - CHOPPER GUNNER (extremely overpowered)
25 - Obviosly Nuke
Best gun steup (mine anyway)
TAR-21 or UMP-45 Silenced
Claymores
Stun x2
Scavenger Pro - oR - One man army pro
Stopping power or coldblooded
Ninja Pro
And theres youre nuke if you play your cards right