TN full-time for U.S firm A &1099 part-time for U.S firm

I have full-time job with TN for U.S company A located in Seattle.

Every weekend/part-time I drive back to Vancouver, B.C; I communte bw Seattle and Vancouver every weekend.

U.S Company B want me as independent/part-time consultant as 1099 without any VISA; it is legal?

Thanks a lot.

//Jerry

You cannot legally work for a US company without a visa.