I met John McCarthy in 1977. In college, a professor (Ruth Davis, I think; SCU EECS department) brought in someone who taught Friedman's "The Little LISPer". By the time I got to Netscape, I had read SICP. I knew enough about LISP to be dangerous.
But as I've said many times, and Netscape principals have confirmed, the reason JS isn't Scheme is because Netscape did the Java deal with Sun by the time I hired on (after I was recruited with "come and do Scheme in the browser"), and that meant the "sidekick language" had to "look like Java".
There was no "chose to write". Netscape management gave the MILLJ order; Netscape source was C (mostly), JS ("Mocha") was supposed to go server-side via "LiveWire" as well as embed in Navigator, and I was a C hacker. These are the reasons for the new language and its first implementation language.