In a saucepan, add the softened butter, chocolate chips, and sweetened condensed milk. Stir gently to mix them together until well combined.

On low heat, warm the mixture while stirring constantly for about 5 minutes, or until everything is melted and smooth.

Once smooth, carefully remove the saucepan from the heat. Pour the rich fudge mixture into a greased dish, spreading it evenly.

Allow the fudge to cool at room temperature for at least 120 minutes. Once set, cut it into squares and serve.