Even as a "nonresident alien" (meaning foreigner) you can use the USCO website and send DMCA takedowns.
But of course, it only works if you send the DMCA to a company that needs to adhere to US law. So it'll work to get Apple or Google to remove the infringing app, but you probably cannot use DMCA to directly pursue the infringers.
What if you hire a US lawyer? You're still not in the US, but I would assume that Apple is still required to follow US law, regardless of where you happen to be.
Even as a "nonresident alien" (meaning foreigner) you can use the USCO website and send DMCA takedowns.
But of course, it only works if you send the DMCA to a company that needs to adhere to US law. So it'll work to get Apple or Google to remove the infringing app, but you probably cannot use DMCA to directly pursue the infringers.