Nicholls (9-4), which tied for first with Central Arkansas in the Southland Conference, won its sixth straight game and will play at No. 1 seed and defending champion North Dakota State next Saturday.
Fourcade gave the Colonels a 10-0 lead late in the second quarter on 1-yard score, one play after Nate Ketteringham was strip-sacked by Sully Laich and Brandon Forntenot made the recovery.
A second field goal by Brady Leach closed the gap but Fourcade threw a 45-yard touchdown pass to Dixon with 4:22 left in the third quarter and Taylor added a 2-yard TD late in the fourth.
Ketteringham threw for 269 yards with an interception with Travis Toivonen making 10 catches for 121 yards. The Fighting Hawks (7-5) rushed for just 44 yards.