At this point, I would not take the 2H line at -13.5 or -14. I would wait to see how the Bucks come out in the 2nd half. Either they are coming back and winning this thing or they will lay down in the 4th quarter, which is not a scenario you want to be involved in laying a large second half number. If they come out strong in the 3rd and pick'em or closer is available you take it then.
Another factor to consider in this game is Jabari Parker having a very strong game against his old team. He clearly wanted to prove to them that they made a mistake in letting him go. His teammates seem to be up the the challenge in supporting him. Something to consider in this one.
Some books, like 5Dimes, offer second half lines on the 2H favorite to come back and win the game... ie MIL -18 +240 in this situation. This is the only kind of second half wager I would consider here.
Further consideration... MIL is the 7th best in the league by avg home margin the 2nd half at +5.0 pts/2h over 7 games. CHI is the 4th worst in the league by 2H margin at -4.9 pts/2H over 7 road games.