Yes, you can dispute a broker price opinion if you disagree with it. You can provide supporting evidence to challenge the broker's opinion. Communicating your concerns with the broker and attempting to reach a resolution or seek a second opinion is advisable.
If your lender ordered the BPO, you’ll need to share your concerns with your lender (including providing any evidence supporting your claim). Ultimately, it will be up to your lender to decide if it believes the valuation is accurate and whether it’s appropriate to get an updated valuation, similar to what it would do in the case of a low appraisal.