Williams played in 10 games and made two starts over the past two seasons with Cleveland and Seattle. He has 10 receptions fo4 92 yards and one carry for five yards in his career.
The 6-foot-3, 307-pound Nunez-Roches played in 34 career games and started 16 in three seasons with the Chiefs. Last year, he started 11 times and finished with a career-high 24 tackles. He had 23 tackles, five tackles for loss and one sack in 2016.
Those moves follow signings earlier this week of free agent offensive linemen Austin Howard, a 6-7, 300-pound tackle who started 88 career games with four different teams, and 6-5, 236-pound defensive end Chris McCain, who has 34 tackles and seven sacks in his four-year career.