Is it God who ordains sin and grants the power to commit it, such as one person harming another, and does the same apply to doing good, taking into consideration that "there is no might nor power except with Allah"?

Allah Almighty is the Creator of all things, including the actions of His servants, both good and evil. Nothing moves or is still except by His permission and will. The harm inflicted by one person upon another occurs by Allah's universal will and decree, even if it contradicts His legislative will. And Allah has profound wisdoms in His decreeing of such matters, for which He deserves all praise.