Preheat oven to 350°F.
Blend flour with 1 cup of the sugar and 1/2 cup of the butter in a large bowl until crumbly.
Press firmly on bottom of 9 x 13 inch pan; sprinkle pecans evenly over the top.
Combine remaining 1/2 cup sugar and 3/4 cup butter in a small saucepan.
Cook over medium heat, stirring constantly, until mixture comes to a boil.
Boil 1 minute until butter and sugar blend into a caramel sauce.
Pour sauce evenly over pecans in pan.
Bake 18 to 20 minutes or until caramel layer bubbles evenly all over.
Remove from oven; sprinkle chocolate chips over the top.
Let stand a few minutes until chips melt, then spread evenly over bars.
Cool until set and then cut into bars.