This is covered pretty well in the Multiple Close Combats section.
The Bear and T-Rex are still in combat and considered front to front. If they weren't touching you would move the Attacker the minimum distance into contact, or if not possible then the Defender, but since they are touching already there's no need to move anything.
(Visualize as if they were on round bases and it doesn't even look so wrong.)
If one or both units had more than one model, the combat reform rule could apply (Victor can reform to bring more models in contact, or Loser can pass Leadership check to do same; if both do it then dice off for which is first). But with single models there's no more maximization to achieve. And it's optional anyway not required.
The players can certainly agree to slide the models to look better, but this really may not be satisfactory. The Norsca player in particular may want the Bear to stay where it is if the Bear is outside the charge arc of the Triceratops. Either player may be looking ahead at flee / pursuit paths and not want to alter them.
The Triceratops, as soon as it moves, must observe the 1" Apart rule. (Unless it can charge something.)
