Is the criteria that the cities had to be named under Spanish/Mexican influence, or just that the names are in Spanish? If it's the latter you could switch Buena Vista, California to Buena Vista, Colorado... it's a significantly larger town, but it was founded and named well after the U.S. began to colonize the region so it might not fit the quiz
San Diego, California
Fresno, California
Naranja, Florida
Pueblo, Colorado
Amarillo, Texas
Rio Rancho, New Mexico
Reno, Nevada
Modesto, California