Well first of i gotta tell you its all about camping and getting a nuke also requires skill.
I can tell you, run and gun does NOT give you a tactical nuke. The easiest way for getting a nuke is sitting in a chopper gunner. The following killstreaks are the best for getting a nuke:
*Harriers (7 kill streak)
*ChopperGunner (11 kill streak)
*tacitcal nuke (25 kill streak)
Once you get harriers i suggest you look for a good spot to hide because once you are in your choppergunner your guy on the ground is defenseless.
There are maps that are good for nukes such as afgan and there are maps whitch are more difficult for getting a nuke like rust. I recommend you not to even try getting a nuke on difficult maps because it only builds up frustration
The basic weapon set up is one of the most inportant things you need to get a nuke. DO ABSALUTLY NOT use scavenger pro. It may seem good but for getting a nuke i really recommend slight of hand (pro)
Secondly your weapons need to have big magazines (in my opinion). You need a weapon that kills the enemy fast... Weapons such as a sniper or a riot shield are not recommended. Weapon such as an RPD or a scar are usefull. I also recommend to use hardline because it isn't always easy. Most people say silenced weapons are the way to a nuke but i say NO. You could use silencers if you stay at one spot the entire time but you do NOT need silencers if you move the whole time. In the beginning of this post i said that nuking is all about camping. I do not camp before i get harriers so that is what i meant.
Patience... I have another tip for you: if you have chopper gunner do not camp somewhere outside, it only takes a predator to kill you.
If you have any questions ask me or reply to this post.Thank you