Final answer:
The noun clause in the given sentence is 'how much he enjoyed the meal', serving as the direct object of the verb 'to tell'.
Step-by-step explanation:
The noun clause in the sentence 'The chicken and rice was delicious, so he couldn't wait to tell them how much he enjoyed the meal.' is 'how much he enjoyed the meal'. Here, this clause is acting as the direct object of the verb 'to tell', which indicates what he couldn't wait to tell them. Noun clauses are subordinate clauses that can function as a subject, object, or complement in a sentence, and they often begin with words like 'how', 'that', 'what', 'who', 'whom', 'whose', 'why', etc.