1. Is it suitable if the nominal power adapter voltage is the same, the power is different?

If the output voltage of your notebook is the same with the adapter, and the wattage requirement for your laptop is lower than the 60W or 90W output of the adapter, it will not damage your laptop, your laptop will only take the amount of power it requires.

E.g. If your laptop needs 45W, then either the 60W or 90W will work OK. If your laptop needs 80W then you will need the 90W one as the 75W one will not be powerful enough.

2. Is it suitable if the nominal power adapter voltage is different, the power is the same?

If the output voltage of your notebook is different with the adapter, and the wattage requirement for your laptop is the same with the 60W or 90W output of the adapter, it must damage your laptop.

E.g. If your laptop needs 45W and the voltage of it is 24, and the wattage of the adapter is also 45W, the voltage is 15W, it wouldn’t work well. It must demage your laptop.