Not only is it possible, they already are. What sin is is a self-contraction that blinds oneself to this nature that is already fully and always there. People "wake up" to this in a flash of brilliance, as it were upon occasions. It nothing attained, as it is instantaneous awareness of ones own being. And what is exposed is that "sin" is the illusion of the mind of separation from that nature. We "live in sin" when we are contracted thusly.If you define "sin" as "being apart from God," is it theologically (not physically) possible for human beings to be singular with God, as opposed to particular from God? IOW, is it possible for humans to be Divine? And what implications does that have for Jesus as both fully human and fully Divine?
Now as far as will goes, I agree with the OP that we can "overcome the world", in this same way as Jesus did. That is to be fully awakened at all times to that Divine Nature. Not just a momentary flash of brilliance, and then we fall back into the habits of 'sin', but a permanent awakened awareness in every lived moment. Our will is simply the intention to align oneself on this path to permanent awakening. It is "not I", not the ego desiring for selfish gain, but "Christ in me" that we awaken to.
How is it Christians claim to have the Holy Spirit within then, and yet deny it theologically and practically?