Even if he was going back to the chelsea and it will not be included in the starting line up and so there's no choice for him other than try to stay at intermilan. Intermilan's owned was also trying to sell its club. That means the future for this club is still remain unknown.
Lukaku has been taking a good decision by staying at inter rather than going back to the chelsea again but i don't even think inter will make him permanent caused by club was facing financial problem.
The owner of inter will be facing the dead line to pay the loan. that's also a very big loan.
Returning to Chelsea not guarantee for Lukaku get regular position under scheme Graham Potter depending his performance in this season with Inter Milan not quite, absent several games with Inter Milan trough still injury I think need for Lukaku scoring goals again if want get regular position at Chelsea. However new manager at Chelsea seems the same if Lukaku can't back to top performance again and seems Graham Potter not easy to give regular place for Lukaku. Still left one half season more and I think if Lukaku can back to quite performance Inter will try several option to extended loan or permanent with Lukaku transfer from Chelsea.