By Teresa Watanabe for The Hechinger Report Oscar Mateo dreamed of being an artist, but after he got leukemia when he was 20, his life plans abruptly changed. The compassionate nursing care he received while hospitalized touched him so much that he decided he wanted to provide the same for others. That impulse led him to the registered nursing program at Mt. San Antonio College in the Los Angeles County suburb of Walnut. But getting there wasn’t…