Fighters are always difficult to compare to ships but this comparison isn't too bad. Both die to a similar number of shots at them, the Nial has a much better chance vs fighters as it doesn't need to worry about staying in arc for firing and has a Dogfight score, however, it's guns are notably weaker than the Haven. The best situation to face off here would be to take some Flyers for the firepower, backed up by Nials for the fighter cover. Either way, in smaller games fighters are definitely worth the purchase.