It would be the team that is ranked higher in the CFP ranking at the conclusion of the season that hosts if teams are tied in conference record and did not play head to head.
Edit: It's actually more complex and involves a win in the final conference game
f only one division champion is ranked entering the final week of conference play, it will host if it wins in that week. If that team loses, a composite of four computer rankings is used to determine the host.
If both division champions are ranked, the higher-ranked team that won in the final week will host. If, in this scenario, neither wins in the final week, the same computer ranking system is used.
If neither division champion is ranked, the aforementioned computer rankings are used.