If the visa is a valid one and the person is eligible to work in the U.S., then there's no problem with issuing them a 1099-Misc; indeed, if someone legally works in the U.S., their wages *must* be documented, either on a 1099 (if a freelancer or independent contractor) or W2 (if an employee). If the person was not legally eligible to work, they should not have been employed and paid (even "under the table," which, by the way, is illegal: the law does not recognize "under the table" payment, and all wages must be documented).