Both are correct, depending on what you mean by 'chance'. There is less chance = lower probability There are fewer chances = fewer opportunities 'Chance' has several meanings, some countable and some uncountable. [ btw The question is 'What do you think?', rather than 'How do you think?']

Chance is a countable noun. So you can say: There are fewer chances of something happening. However, you can also say: There is a lesser chance of something happening. Both phrases have the same meaning, the first one just emphasizes there might be more possible chances, and the second indicates just one. I also added “happening” at the end because it’s more natural to say. Hope that helps!