The US Air Force Fact Sheet below explicitly sites the Büchel Air Force as a German location of US nuclear weapons. The US government has not admitted they are located here in other publications or queries.
This Air Force Base Training Manual* defines protection level 1 stockpile mentioned in the above fact sheet. A “protection level 1 stockpile” is air force jargon for a stash of nuclear weapons, as its own open source documents show. The Shaw Air Force Base Instruction 31-102 6, of Dec. 6, 2012, is an Air Force instruction manual available online that openly defines protection level 1 (PL 1). In instruction 4.7.1., it says, “Examples of PL 1 resources include nuclear weapons and … systems critical to the success of active nuclear missions…”
*Download here if the previous link is removed.