Combine first five ingredients in a saucepan.
Bring to a boil, stirring constantly; then reduce heat to simmer and cook without stirring to the soft-ball stage (235F to 240F).
Remove from heat and add butter and vanilla, but do not stir.
Let mixture cool to lukewarm, then beat until its gloss disappears.
Add nuts and chips.
Spread in greased pan.
Cut in squares when cold.