Ruben Nino-Guerrero (Nino) appeals the 57-month sentence he received following his guilty-plea conviction for illegal reentry in violation of 8 U.S.C. § 1326. For the first time on appeal, he argues that the 16-level enhancement he received, pursuant to U.S.S.G. § 2L1.2(b), for having been deported following a prior aggravated felony conviction was error.

The instant appeal is barred by the waiver-of-appeal provision in Nino’s plea *793 agreement, which waiver was knowing and voluntary and is enforceable. See United States v. Melancou, 972 F.2d 566, 567-68 (5th Cir. 1992); Fed.R.Crim.P. ll(b)(l)(N). The Government seeks to enforce the waiver, and Nino has abandoned any challenge to the validity of his plea or the waiver provision by failing to brief it. See United States v. Story, 439 F.3d 226, 231 (5th Cir. 2006); see also United States v. Green, 964 F.2d 365, 371 (5th Cir. 1992). Accordingly, the district court’s judgment is AFFIRMED.