Usage patterns
〈物〉の詰め合わせan assortment of ~
This is an assortment of cookies.
〈物〉を詰め合わせにするto make ~ into an assorted set
I put various sweets together into an assorted set.
詰め合わせを贈るto give an assortment as a gift
I gave an assortment of fruit as a thank-you gift.