Line an 8x8-inch baking dish with parchment paper, leaving some overhang for easy removal.
In a medium saucepan, combine the semisweet and milk chocolate chips with the sweetened condensed milk over low heat. Stir continuously until the chocolates are fully melted and the mixture is smooth.
Remove from heat and stir in the vanilla extract until well combined.
Pour half of the chocolate mixture into the prepared baking dish and spread it evenly.
Pour the caramel sauce over the chocolate layer, then sprinkle the toasted chopped pecans evenly on top of the caramel.
Pour the remaining chocolate mixture over the pecans, spreading it evenly to cover all the layers.
Gently press down with a spatula to ensure everything adheres.
Sprinkle a pinch of sea salt over the top for a sweet and salty contrast.
Refrigerate the fudge for at least 4 hours, or until completely set.
Once set, lift the fudge out of the pan using the parchment paper overhang and cut it into squares.
Notes
Arrange the fudge squares on a decorative plate and drizzle with additional caramel sauce before serving for an elegant finish.