Jackson's commitment comes 10 days after Stanford receiver Keanu Nelson announced he would play his final season at BYU. In February, the Cougars signed former UTEP receiver Jordan Leslie, who also has one year of eligibility remaining.
Jackson, 6-foot-2, 215 pounds, is from Fresno, Texas.
He started the 2013 season as a starter for the Cornhuskers, and finished with 33 tackles, 20 of them solo stops. However, his role lessened with each passing game, and he did not play in Nebraska's final three games after starting its first three.
Jackson was rated as the 27th-best safety in the country out of high school and chose Nebraska over offers from Baylor, Arizona State, Missouri, Oklahoma and Utah.
Jackson visited BYU earlier this week and toured the campus and met with Howell and other coaches.
Only one of BYU's starting safeties from 2013, Craig Bills, is returning to the team in 2014 because all-independent safety Daniel Sorensen graduated and could potentially be selected in May's NFL Draft. Jackson will likely compete with converted cornerback Rob Daniel, Notre Dame transfer Chris Badger and sophomore Kai Nacua for the starting spot opposite Bills.