Yes you can freeze chives and green onions to keep them fresh longer and make them last longer as well.
When freezing chives and green onions you should chop the green onions and chives up into small pieces and then place them in Ziploc bags or other freezer safe bags.
Or place the cut up green onions and Chives in freezer safe sealed container and then place them in the freezer.
Just don't overfill the bag or container with the green onions and chives so that they have airspace around them.
Then when frozen the green onions and chives should last in the freezer for up to a year before they begin going bad.
However for best taste and freshness use the green onions and chives within 6 months of freezing them although they will remain safe for a year or more in the freezer.