Hi Jake,
Thank you for pointing me to the right direction! While the blog you shared did not work for me, it was very insightful. I had to use tiktoken.get_encoding(“cl100k_base”) with the ChatCompletion, ChatGpt 3.5 turbo model, plus adding a space before a given word to get the right tocken id, then it worked 
I’m leaving this link for the forum with the details in case anyone is interested: [Reproducible] gpt-3.5-turbo logit_bias -100 not functioning
Thank you again for your time and attention