The challenge Nuclear Killer (now referred to as "NK") is one that cannot easily be scoffed at.
The main goal: 30 kills without dying.
This requires a lot of practice and a lot of patience, it's very difficult to complete.
First, avoid certain game modes that require a set kill limit or have very confining time restraints. Team Deathmatch (TDM), Search and Destroy (S&D), and Free For All (FFA) should be avoided. It's not impossible to complete NK in these game modes, just much harder. FFA is the most possible of the above listed, but it requires a complete match, all 30 kills and no deaths.
If a player is using FFA to complete NK, keep on the move. Use an SMG with a silencer, Ghost, Flak Jacket, and Scavenger to ensure that stealth and mobility is maintained with survivability. Use a weapon you're comfortable with.
Domination or Headquarters are the best recommended for NK. This will require knowing the hot points of a map for whatever map one is playing; look at the heat map of past matches in the Player Track Record under Barracks and decide where these hot spots are. In objective based games, these hot spots are likely to be placed right around the objective.
Try camping around the objective and sticking to places that have only one or two paths or openings. Make sure you are in view of the action but not right in the aim of fire. A silencer/suppressor will ensure stealth is maintained, but beware of the range reduction.
A main-stay of survival is stick close to walls and know when a kill streak is coming. Lightning Strikes are devils, and if one is suspected to be on the way, stay indoors and in cover. Hunter Killers can be destroyed with an expertly placed EMP grenade, but Hellstorm missles have to be avoided under cover.
Air Support will be dangerous, but with the right perk cocktail can be easily avoided. Choose perks wisely. For those on the move, Ghost is recommended. Those camping, should use Blind Eye. Flak Jacket is invaluable to ensure a stray grenade does not ruin a perfect streak.
Continued in part 2.