45 CFR §309.60

1. (a)Under the Tribal IV-D plan, the Tribe or Tribal organization shall establish or designate an agency to administer the Tribal IV-D plan. That agency shall be referred to as the Tribal IV-D agency.
2. (b)The Tribe or Tribal organization is responsible and accountable for the operation of the Tribal IV-D program. Except where otherwise provided in this part, the Tribal IV-D agency need not perform all the functions of the Tribal IV-D program, so long as the Tribe or Tribal organization ensures that all approved functions are carried out properly, efficiently and effectively.
3. (c)If the Tribe or Tribal organization delegates any of the functions of the Tribal IV-D program to another Tribe, a State, and/or another agency or entity pursuant to a cooperative arrangement, contract, or Tribal resolution, the Tribe or Tribal organization is responsible for securing compliance with the requirements of the Tribal IV-D plan by such Tribe, State, agency or entity. The Tribe or Tribal organization is responsible for submitting copies and appending to the Tribal IV-D plan any agreements, contracts, or Tribal resolutions between the Tribal IV-D agency and a Tribe, State, other agency or entity.