Yes absolutely. That was done through the ideal of the Chakravartin and Aswamedha Yagya. Bharat already existed as a nation with fairly distinct boundaries described as Himalaya on the one side and the sea on the other three sides. It also had and still has due to the continuity of civilisation, a distinct culture and a clear spiritual identity. All the needed ingredients of a nation were already there during the Mahabharata time and even earlier as well.