I have one of "those" wort chillers, or rather I should say that up until last week I HAD one. I have a very plain entry level copper tubing IC with the plastic hoses held on by hose clamps. The inlet hose would periodically (and unpredictably) start to leak, so I had to keep an eye on it each time I started to chill, to tighten it down. I finally got fed up, and went to HD and bought compression fittings and garden hose adapters for it.
Problem solved:
The fittings I bought at Home Depot (all Watts) are:
two #A118 3/8" OD compression fitting x 1/2" FIP w/ insert (you will throw the insert away)
two #A663 3/4" x 1/2" Male hose to MIP adapter
one #A662 3/4"FH x 3/4"FH dual female hose adapter
These items ran $19 incl. tax.
You will need teflon tape to assemble the first two items.