When you bite off more than you can chew, you take on more work, responsibility or problems than you can handle.
“I think we’re biting off more than we can chew with this acquisition”. The speaker here is expressing fear that buying the other company will turn out to be more than her company can manage.
Let’s see other examples :
– I guess we bit off more than we can chew bydealing with the new strategy.
– She has two jobs now. I assume she’s bitten off more than she can chew.