Remove the TB. The coolant line is pressed into it. You can remove it by twisting it out. If it wont twist out, I'd cut that itchbay off flush with the housing. After you get it out, there is a myriad of solutions.
Press a metal "freeze plug" into the hole.
Tap the hole and screw a pipe plug into it.
Get some JB weld stick. Mix it up, and blob that junk in the hole.
Done deal.
I used the #2 solution on mine, but I also added some JB to the threads cause I'm just that way.
Beats the hell out of a hose with a bolt screwed into it,...that'll look all Klondike Kat.
Wouldn't you agree
@mikestang63 ?