Yeah, noone carries more than 8 OLinemen on 53 man roster, so if you acquire one OT via. FA or 1st/2nd round pick you have...
Leno, addition (starting tackles)
Massie (swing tackle)
Sitton, Whitehair, Long (starting interior)
Kush (backup G/C), Morgan (backup G/T)
That means Nelson would kinda be a luxury pick, especially when you consider talented players available at high impact, playmaking positions like CB (Fitzpatrick, Jackson) and OLB (Chubb, Key, Ferrell).
And I'm certain Bears will have an opportunity to choose between Jackson, Ferrell, Nelson, Ridley at #8 (plus a potential trade down), so it will be interesting what direction they go.