Cool topic. While the OP mentioned some amazing quarters in NU history, I will try to go with some different ones that I remember.
1991 vs. Oklahoma, 4th quarter - NU outscores OU 9-0 to win 19-14 and clinch NU's first Orange Bowl in a few years. It was a freezing cold game, played in rain & sleet. NU drove 80 yards in 10 plays, led by Calvin Jones, including a 4-yard gain on 4th & 1 from OU's 19 yard line (Osborne eschewed the FG attempt, due to field & weather conditions). Jones scored from 15 yards out the next play.
1992 vs. Colorado, 1st quarter - while NU only outscored CU 7-0 in this quarter, the Huskers clearly showed their dominance from the opening gun. Travis Hill intercepted Koy Detmer on the first play of the game, leading to a quick score. While NU scored more points in the 2nd and 4th quarters of this game, it was the early dominance that had Memorial Stadium all game long on Halloween night.
1997 vs. Tennessee, 3rd quarter - NU breaks open a 14-3 game at halftime by outscoring Tennessee 21-6 in the 3rd quarter. The blowout victory leads just enough voters in the Coaches Poll for NU to end up with the Coaches Poll National Championship, and the way cooler trophy (suck it Michigan)
2002 vs. Texas A&M, 4th quarter - it was the David Horne show in College Station, as NU comes back from a big defecit. NU outscores A&M 17-7 in the 4th quarter to win 38-31.
2009 vs. Oklahoma, 4th quarter - NU wins this game 10-3 over OU in Lincoln, and both teams were actually scoreless. But, being at this game, the 4th quarter was so memorable. By the 2nd half, the NU offense couldn't do anything, but the defense just kept on making the big plays to keep NU ahead. OU's drive summary in the 4th quarter ended like this: INT, turnover on down, INT, INT. All of those drives reached Nebraska territory, and the fans were willing the defense to keep making stops.
2012 vs. Michigan State, 4th quarter - the score was only 14-7 in this quarter in favor of NU, after MSU goes up 24-14 early in the 4th quarter. There was also a MSU INT TD return called back, which enabled NU to mount a comeback in the late stages of the game. Martinez's pass to Kyler Reed on 4th and 10 was the huge play that got NU into scoring position. A controversial pass interference on Kenny Bell sets NU up 1st and goal and Martinez hits Jamal Turner in the corner of the end zone for the winning TD.
2015 vs. Michigan State, 4th quarter - again NU makes just enough plays when I thought NU had lost the game numerous times in the game and 4th quarter. NU outscores MSU 19-7 in the quarter.