Do you know if nickel contains amalgam?

No nickel amalgam! The exact metal composition in a amalgam filling varies, but it is approximately 50% mercury, 30% silver, and the remaining amount is a mixture of other metals like copper, tin, and zinc. Note that some of these dental amalgams can also have a much higher proportion of copper, so that the amount of silver for these types could be even less than 30%. I am not aware of any nickel content.