This is the question that the Supreme Court has decided to answer in Gundy v. United States:
Whether the federal Sex Offender Registration and Notification Act’s delegation of authority to the attorney general to issue regulations under 42 U.S.C. § 16913 violates the nondelegation doctrine.With the cert grant in Gundy, it's important to preserve this issue. But don't assume it's a dead-bang winner. The last time the High Court relied on the nondelegation doctrine to strike a federal law was in 1935.