In general, darker malts have more concentrated flavor, since the darker compounds created in Maillard reactions and/or caramelization (pyrolysis) and carbonization at high temperatures have a stronger taste.
However, although color is a significant indicator, it's only a one dimensional indicator, and doesn't capture all the details of flavor. For example, compare a crystal malt and roasted malt of the same color. With the crystal, conversion of the sugars produces more caramelization, leading to the series of sugar-derived flavors (caramel, toffee, raisin) that we see with crystal malts, while roasted regular malts produce bread, biscuit, coffee, and increasing levels of roastedness. Another example of flavor differences with same color is Carafa malts, which come in regular and dehusked, both producing the same amount of color, but different flavor.
One way to know for sure how a given malt will taste is to brew a small tea from the steeped crushed malts and sample. While it's possible to get a general idea of a recipe by looking at the ingredients, to take it to the next level requires a pilot brew in order to fine tune the recipe to the specific ingredients, the equipment and process used.
Naturally, the more detailed the recipe, the easier it is to pair ingredients from the recipe with what is available, or that substitutions can be made. In the case of a recipe that simply asks for Chocolate malt, then one hopes that the quantity is just a few ounces so the flavor impact is low, allowing any chocolate malt to be used. In larger quantities, you could try to refine the recipe from knowledge of how the final beer tastes, taking into account the ingredients you have available. If this isn't possible, then you may simply have to brew, and accept that this may not be exactly on target, requiring a few tweaks and a second attempt. It's not uncommon for brewers to tweak and brew a recipe 5 or more times in order to specifically hit the target they are looking for.
