How long will previously-frozen vacuum-packed chicken last in the fridge?
My answer to the other question still applies: vacuum packing will not prevent most foodborne pathogens from multiplying.  In the case of chicken, it will stop campylobacter (which needs small amounts of oxygen) but will not stop salmonella or listeria.

Here's how you can determine if thawed, previously frozen chicken is still safe to eat: 


When freezing, marking the freezing date on masking tape and stick it on the package
When thawing, mark the thawing date similarly
To determine if it's still good: subtract the freezing date from the original expiration date, and see if it's been that many days since you thawed it


This method works because spoilage is halted by freezing... but not reversed.  Once you thaw, the process picks back up where it left off.  A few days in the fridge after thawing should be fine, assuming you don't wait until right before expiration to freeze the chicken.