James J. Postl was named president, Nabisco Biscuit Co., Parsippany, N.J., from president, Nabisco International, New York. Mr. Postl replaces Ray Verdon, 53, a native of Canada who formerly served as chief executive of Nabisco Ltd., Toronto. Mr. Verdon is returning to Nabisco Ltd. as chairman. Mr. Verdon has overseen the cookie and cracker business since August 1993, extending the SnackWell's brand into salty snacks, ice cream, yogurt and other products, and leading Nabisco's push into the breakfast aisle with SnackWell's and granola breakfast bars. Heavy investment in new products generated strong third quarter sales at Nabisco Holdings Corp. - up 5% to $2 billion - but disappointing earnings. Operating income fell 10%, to $196 million.