Nabisco, Parsippany, N.J., has acquired Gumz Alimentos F.A. Industria e Comircia, a Brazilian dairy company. Terms of the transaction were not disclosed. Gumz is No. 1 in chocolate-flavored milk in its home states of Santa Catarina and Parana. The company also produces Sant' Ana milk and milk-based products. Sales totaled $24 million in 1994.