Yes most pigs and especially wild pigs are immune or resilient to snake venom and will be just fine if the snake bites the pig.
Some pigs in the wild will actually attack snakes and even kill the snake even after the snake bites the pig.
So the snakes are pretty defenseless against most pigs because the snake venom will usually do nothing to the pig to kill them or make them sick.
The pig will likely either eat the snake or when at least kill the snake especially if the snake tries to or does bite the pig.
Even pigs that are kept at farms are immune to snake venom as well.
I wish humans were immune to snake venom but sadly we're not and if a human gets bit by a poisonous snake they need medical attention right away to prevent death.