Yes, "go" is a verb in the conditional mood in this sentence. It is indicating a hypothetical situation where the action of going to the store is dependent on the outcome of not having anything for dinner. The conditional mood is used to express actions that are contingent on a certain condition being met.
How is it a conditional mood?
In this sentence, the word "if" signals that the action of going to the store is dependent on a specific condition, which is not having anything for dinner. The conditional mood is used to express this kind of dependency or uncertainty. In this case, the verb "go" in the conditional mood is expressing a hypothetical situation where the action is only carried out if the specified condition is met.
