Not only does Howley look good compared to Nobis, Howley also compares well to others who played his position.
Nobis vs. HOF MLB's of his era
Nobis
5 Pro Bowls, 1 All-NFL, All-60's
Nitschke
1 Pro Bowl, 3 All-NFL, All-60's, NFL 75th Ann. Team, MVP '62 Title, 2 rings
Butkus
8 Pro Bowls, 6 All-NFL, All-60's & 70's, NFL 75th Ann. Team, DPOY '69 '70
Buoniconti
2 Pro Bowls (6 AFL All-Star), 2 rings
Lanier
6 Pro Bowls (2 AFL All-Star), 1 ring, NFL 75th Ann. Team
One thing you can tell from this list is that the Hall loves MLB's. That's about the only thing that might help Nobis, because his credentials don't match any of the above (He's Buoniconti without the rings).
Howley vs. HOF OLB's of his era
Howley
6 Pro Bowls, 5 All-NFL, SBMVP, 1 ring
Bobby Bell
3 Pro Bowls (6 AFL All-Star), 1 All-NFL, All-Time AFL Team, All-70's, 1 ring
Dave Wilcox
7 Pro Bowls, 4 All-NFL
I look at this and ask (and not for the first time) why Howley wasn't inducted in 2000 instead of Wilcox. Not many OLB's in the Hall from this era though, especially when you consider that the OLB's who played outnumbered the MLB's about two to one.