Why does your ex favor your kid over the others?
You state that there are court orders. Are they both through Nevada?
You state that he is honoring one court order and ignoring the other. The other baby momma can take Dad to court to try to enforce the order. She can ask that the child support be handled by Child Support Enforcement (or whatever it's called where she is), so that his arrears are documented, and the deadbeat can lose his license, lose his passport, have his accounts frozen, have his tax refund intercepted, etc. Oh, and by the way, if he's been working under the table but still paying you $3K a month, hopefully he has been filing something plausible for income taxes.