Well for starters you need 2 troop choices for a legal army, and the one you do have is (And Im putting this as nicely as I can) target practice. They will get blown away easy.
For 1500 points these have similar numbers to Space marines, which is BAD for Orks, seeing as their whole thing is swamping, basically.
I dont like to be harsh but in any game this will get killed with ease-I recommend revising it. Not just the list, the strategy, I have some tips that might help-
Drop the weirdboy. For the points they aren't that good at all
SO many more boyz (Or at least enough for a legal army

)
Lose the red paint on the trukk, and get 2, and 2 meks if anything-One with each nob squad.
Deffkoptas may be worth replacing with stormboyz. Yes, alot CAN go wrong but with good rolls and good numbers they are a great weapon.. for a while
May want to consider a Basic Battlewagon. This kind of army youve made wont be able to deal with large numbers so a nice big KilKannon Would work a treat
Hope I helped!