25 U.S.C. § 3746
Tribal immunity
Nothing in this chapter shall be construed to affect, modify, diminish, or otherwise impair the sovereign immunity from suit enjoyed by Indian tribes.
( Pub. L. 103–177, title III, § 306 , as added Pub. L. 103–435, § 12(b) , Nov. 2, 1994 , 108 Stat. 4572 .)