The 23-year-old Recari, a tour rookie who made cuts in only three of her first 13 stroke-play events this season, rebounded from a bogey on the No. 17 with a par on the 18th for a 2-under 70 and a 14-under 274 total on the Blackhawk Country Club course.
Nocera birdied the final hole for a 70.
Michele Redman (76) and Karine Icher (70) tied for third at 12 under.
"I'm thrilled," Recari said while clutching a large bouquet of flowers. "I'm very proud of how I handled myself out there. I did not allow the nerves or (look) any further than what I had to do right in front of me."
"That was a great experience because I had some much adrenaline, and then I just felt so calm when I was standing on the putt," Recari said. "That was fun for me ... but this is my job and I still have to keep it fun and focused."
Cristie Kerr missed a chance to overtake Ai Miyazato for the No. 1 ranking, closing with a 70 to tie for fifth with Wendy Ward (72) at 11 under. Kerr needed to at least share third to take the top spot.
"I figured if I could have another low round, I could manage to do it," Kerr said. "But the weather conditions were a lot tougher today and I didn't quite hit it good enough to get it done. Top five, hitting it the way I did this week, I think is a victory."
The win ended a 14-month world victory drought for Recari, who nearly tripled her career winnings with the $165,000 first-place prize.
"She did a really great job," said Redman, who played with Recari in the final group. "She played it smart, she got some good breaks and she hit a lot of really good putts."
Recari hadn't had much success since leaving the LET. That changed when she calmly sank a 2-foot putt on the 18th, then immediately jumped into the arms of her caddie under a steady drizzle of rain.
The weather affected the final round and made it tough to gain ground after the tournament began in 95-degree heat Thursday.
The leaders found that out the hard way.
The 45-year-old Redman, seeking her first win since 2000, went into the final round tied with Recari and Ilhee Lee but couldn't hold on.
After falling a stroke behind when Recardi birdied No. 6, Redman pulled even with a birdie on the ninth but fell behind again after pushing her tee shot right on the par-3, 10th. The ball settled in thick, wet rough and Redman's chip shot fell 3 feet shy of the green. She settled for bogey.
Lee, a rookie from South Korea who nearly quit the tour this year after missing seven straight cuts, bogeyed three of the first four holes Sunday and fell off the pace with a 78. Lee tied for 15th at 6 under.
Recari had her problems, too.
She birdied the third but gave the stroke back two holes later with a bogey on the par-5 fifth. A birdie on the sixth put her in front again and she added birdies on Nos. 13 and 14.
Recari's bogey on 17 coupled with Nocera's birdie on the 18th cut the lead to one. With Nocera standing close by, Recari avoided a playoff by two-putting from just off the front of the green.
Brittany Lincicome, the first-round leader after a course-record 61, shot a 70 to tie for eighth at 9 under.