Need a Dragonite Killer

Nah, i don't think that's a very good Dragonite killer. Try to find a good Dewgong with Frost Breath and Blizzard or Cloyster is decent as well. Lapras obviously is the best one but it's hard to come by. Wigglytuffs are good as well but not so much if they have Steel Wing because then not very effective attacks become super effective.

In case you dont have lapras, Dewgong. No doubt.

Cloyster is easier to find but it is made of glass. Heavy attack but very low health. Even dodging you won´t last long