Defining a best restaurant near Qualcomm Stadium is a tough task, because it often depends on what brings you to the stadium area of San Diego. The "Q", the stadium's nickname, is home to the NFL's San Diego Chargers and the SDSU Aztec football games, but nearby neighborhoods are popular places for business stays, home to San Diego's best shopping and residential areas.
The other determinant is how far you're willing to walk to the stadium or from a trolley stop, if applicable. Though there's plenty of fast food options near the stadium, options within a short walk are slim. McGregor's Bar is walkable and a festive pre-football game choice as it's a sports bar by nature. Outside of McGregor's, you're looking at dining in the Mission Valley, Mission Gorge, Grantville or even the North Park neighborhoods a mile or two away.
If reliant on the trolley, consider eating in Oggi's or Gordon Biersch in the Mission Valley area and then hopping back on to Qualcomm Stadium trolley stop. Keep in mind that San Diegans are avid users of the Uber taxi app. Either this mode of transport or your own car enables an easy journey to any of these restaurants.