Kardashian gave birth to the couple's first child, daughter North West, in June.
A photo posted on Instagram shows a screen at the stadium that reads "PLEEEASE MARRY MEEE!!!" - in typical West font - above a black-clad orchestra. Another shows Kardashian showing off a diamond ring with a smiling West behind her.
The Kardashian clan has a series of reality shows on E! and after initially saying it didn't have cameras at the stadium, the network said late Tuesday it did have cameras there to capture the moment.
Kardashian was previously married to NBA player Kris Humphries. Their divorce was finalized in June after they were married for 72 days in 2011. Her first marriage was to music producer Damon Thomas in 2000.
West is currently on a tour with Kendrick Lamar. "The Yeezus Tour" will visit the SAP Center in San Jose on Tuesday night. Earlier Monday, he attended the Hollywood Film Awards in Beverly Hills, presenting Steve McQueen with the Hollywood Breakout Director Award.