The winner of the inaugural tournament in 2009, Stanford had an 11-under 133 total at Guadalajara Country Club. The Texan won the HSBC Women's Champions in Singapore in February for her fifth LPGA victory.
Park, from South Korea, had a 68.
Cristie Kerr was third at 8 under after a 69.
Lewis has a 58-point lead over Park with two events left in the player-of-the-year points race, putting her in position to become the first American to win the award since Beth Daniel in 1994.
Michelle Wie, tied for the first-round lead with Stanford and Kung after a 66, had a 75 to drop into a tie for 12th at 3 under. Wie won the 2009 tournament.
Top-ranked Yani Tseng also was 3 under after a 71.
Ochoa was 1 under after a 72. The Mexican star won 27 LPGA titles before retiring at age 28 in 2010. She missed the event last year before the birth of son Pedro in December.
Suzann Pettersen, coming off consecutive victories in South Korea and Taiwan, was even par after a 74.