Finely chop pistachios in a food processor. Combine 2 cups milk and chopped pistachios in a saucepan. Slowly bring to a boil, stirring frequently. Remove from heat. Allow to cool, then chill in fridge for 2 hours.
Remove nut and milk mixture to a mixing bowl. Combine half-and-half, sweetened condensed milk, and pudding. Stir well, trying not to allow lump of pudding to remain.
Pour mixture into the bucket of ice cream freezer. Fill bucket to fill line with milk. Insert dasher and put the lid on the bucket.
Place the bucket in ice "tub." Attach the motor and plug in. Alternately add ice and rock salt around the bucket. I recommend using crushed and a heavy hand with the salt. This will give the ice cream a creamier consistency. The ice cream is finished when the motor can no longer move the dasher in the bucket. Remove any leftover ice cream to a separate container to put in your freezer. Do not put ice cream bucket in freezer.