Is the kingdom Jesus talked about with Nicodemus the same as the future earthly kingdom?
Yes. The kingdom Jesus mentioned to Nicodemus is the same kingdom. As the context states, 'the kingdom is the kingdom of the king,' and it is 'this kingdom that's coming upon the earth.' No unbeliever will enter it, whether flesh and blood or otherwise.
Les explains that the kingdom Jesus spoke of to Nicodemus is the same kingdom that will come upon the earth. In John 3, Jesus told Nicodemus, 'Except a man be born again, he cannot enter the kingdom of heaven.' Les points out that this is the same kingdom, the kingdom of the king. It is the future earthly kingdom where flesh-and-blood survivors of the tribulation and Armageddon will enter. No unbeliever will go into that kingdom, whether flesh and blood or otherwise. These survivors will come up from year to year to Jerusalem.
Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God.