Francisco Sáez arrived in Silicon Valley last January. He had just dropped out of college and, like many 21-year-old app developers, the Chilean national was teeming with ambition — wide-eyed and ready to pursue his dreams of becoming an entrepreneur.

For Sáez, the trip meant everything. He had been dabbling in side projects and web ventures throughout his four years as an engineering student in Santiago, Chile, but Nixter — an app that shares crowdsourced data on hot nightlife destinations — was the first to gain real traction. He and his three partners had already raised some $100,000 in early funding, and in 2011, received an award from CORFO, Chile’s government-run incubator program.

It was because of this award that Sáez found himself standing next to his brother and two friends in San Francisco last January. And it’s because of US immigration law that he found himself back in Santiago nine months later.