Heat oven to 350F.
Grease 15x10x1" jelly roll pan with nonstick cooking spray.
Drain canned sweet potatoes, reserving 3 tbs. syrup.
Mash potatoes in bowl, combining with reserved syrup.

Whisk together flour, baking powder, allspice,
cinnamon, cloves and salt in medium-sized bowl.
In large bowl, beat butter and sugars together on medium
speed until smooth and slightly lightened in color.
Beat in eggs, one at a time, mixing well. On low speed, beat in half the flour mixture.
Beat in mashed sweet potatoes, then remaining flour mixture.
Fold in the mini-chips and 3/4 of the chopped nuts.

Scrap batter into prepared pan, spreading to edges,
smooth top. Sprinkle with remaining 1/2 c. chopped pecans.

Bake at 350 degrees for 35 to 40 minutes.
Cool in pan on wire rack. Cut into bars.