From a March 21, 2023 report by Adam Shaw of Fox News:

Officials say the Rio Grande Valley Sector — one of the busiest sectors along the border — has seen a more than 900% increase in Chinese nationals over the same time last year. Across the southern border, there were 55 encounters of Chinese nationals in February 2022; there were 1,368 in February 2023.

This makes total sense since it is a well-known fact that China shares a border with Mexico.

When people think of the worsening situation at the U.S.-Mexico border, people first think of border crossers from the Mexico, Central America, or certain other Western hemisphere countries (most prominently Cuba, Haiti, and Venezuela). But there are growing numbers of people transiting through Mexico to the U.S. border, either to claim a fear of persecution or try to sneak across, from countries well outside the Western hemisphere (China, Eastern Europe, Africa, etc.). This report highlights the extreme nature of some of the increases.