In general, a nonresident alien may be an owner in any business structure--corporation, limited liability company, or partnership. The one significant restriction is that a corporation cannot elect S-corporation status (i.e. avoid double-taxation) if an owner is a nonresident alien. Most startups with nonresident alien owners choose to organize either as a limited liability company or a C-corporation.
The appropriate business organization legal structure is driven primarily by tax issues rather than immigration issues. Your CPA can best advise you which business structure is most advantageous for you based on your partner's and your particular financial circumstances.
Note that there is a visa designated for immigrant investors; depending on the size of the startup, you may want to explore this avenue for bringing your business partner to the U.S.
Brandon Okes
General Counsel, P.C.
bokes@generalcounsellaw.com