Preheat the oven to 350° and position 2 racks in the lower third. In a large bowl, using an electric mixer, beat the butter and brown sugar until fluffy. In a small bowl, dissolve the baking soda in the warm water, then beat it into the butter mixture. Add the eggs, vanilla and orange zest and beat at low speed until combined. Beat in the flour and salt until barely combined, then mix in the oats, cranberries and chips.
For each cookie, use an ice cream scoop or a large spoon to scoop 3 tablespoons of the dough onto parchment-lined or nonstick baking sheets; space them 2 inches apart. Bake the cookies for about 13 minutes, until lightly browned and crisp around the edges but a little soft in the center; shift the pans from top to bottom and front to back for even baking. Let the cookies cool for 10 minutes on the baking sheets, then transfer them to a wire rack to cool completely.
The cookies can be stored in an airtight container for up to 1 week.