Nebuchadnezzar had a dream. In his dream, he saw an image made up of a golden head, chest and arms made of silver, belly and thighs made of bronze, iron legs, and feet made of iron and clay. These represented kingdoms, and the golden head represented the Babylon kingdom. Nebuchadnezzar also saw a stone, and that represented Christ, or rather the kingdom of Christ.
In Daniel’s dream, he saw 4 beasts. These 4 beasts represented the kingdoms Nebuchadnezzar saw. Nebuchadnezzar saw the building of kingdoms via conquests of land as though it was something to admire. Daniel saw those kingdoms as beasts, probably due to wars and casualties involved. Nebuchadnezzar saw his kingdom as a golden head while Christ as a stone. Daniel, on the other hand, saw Christ as one like the Son of Man.
The 2 men saw 2 different representations of the same matter. I guess it got to do with the state of their mind. Daniel was humble towards God, while Nebuchadnezzar was not. May we have the right view and attitude towards God.