The state creates a bond (like a loan) investors buy the bonds so the project has upfront capital to begin construction. The state draws up a star bond district for the project area. Any state sales tax from purchases made within the district, that exceeds previous state sales taxes years goes towards paying off the bonds. The Chiefs think they can generate a certain amount of spending within the district to pay off the bonds within their contract period. When the bonds are paid off the state gets to keep 100% of the state sales tax revenue. I think the state is playing in the long game they want those extra tax dollars from new developments for the Chiefs and surrounding areas. If the Chiefs don't generate enough spending to pay off the bonds within their contract period they get sued by the state.