By Nick Selbe The former first-round pick had his best season in 2021. The Chargers have reportedly agreed to a three-year, $60 million contract with star wide receiver Mike Williams, with $40 million guaranteed,according to Ian Rapoport of the NFL Network. Williams’s rookie contract expired after the 2021 season, and he now remains in Los Angeles on a multi-year deal in lieu of the franchise tag. The 27-year-old is coming off the best year of his career, playing in 16 games with 76 catches, 1,146 yards and nine touchdowns. Injuries plagued Williams at the start of his career, as he was limite…