koh-teh-KEE-noh
Here's a breakdown of the sounds:
* koh: like the "co" in "coat"
* teh: like the "te" in "ten"
* KEE: like the "kee" in "keep"
* noh: like the "no" in "know"
You can also hear the pronunciation by searching for "cotechino" on a pronunciation website like Forvo.