If you had no income of any kind, then instead of fighting the residency determination, you could just file a return with zero income and owing zero taxes. However, the notice may indicate some CA-source income that you forgot about, like a last paycheck, or bank interest, or sale of a home or other asset. If you were not a CA resident according to publication 1031 but did have CA source income, you owe CA tax on that CA source income using a non-resident return.
