How long can you freeze raw chicken before it seriously affects its taste?
The change in flavor is mainly affected by packaging and how long before it gets frozen.

Packaging: If you have vacuum sealed chicken it will last quite a while. It won't get freezer burnt, dry out or pick up flavors from other freezer occupants. I would say properly packaged will last months to a year range depending on your taste buds.

Time before freezing: I have a habit of buying meat to cook right away, but end up freezing it raw several days after the fact. I then see it a week or two later and pull it out to cook. It never tastes as good as when I freeze it immediately.