In a heavy saucepan over very low heat, melt the chocolate chips with sweetened condensed milk and salt.
Remove mixture from heat.
Stir in vanilla essence and chopped nuts.
Spread mixture evenly into an aluminium foil-lined square pan (approx 8in/ 18cm).
Refrigerate to chill (approximately 2 hours).
Turn fudge out onto a cutting board and remove the aluminium foil.
Cut your yummy fudge into squares, and either eat the lot, or store (covered) at room temperature.