NextDecade Corp., which was facing concerns about its financial strength at the beginning of the year, has received a $30 million injection and taken major steps in the last few weeks toward sanctioning a liquefied natural gas (LNG) export project in South Texas.

The Houston-based LNG developer in March said in its annual report it had less cash on hand than necessary to cover this year’s operations. It noted there was “substantial doubt about the company’s ability to continue as a going concern.”

“We have incurred operating losses since our inception and management expects operating losses and negative cash flows to continue for the foreseeable future and, as a result, we will require additional capital to fund our operations and execute our business plan,” the...