Can lift be equated to how much air is moved?
First off, your calculation for 9.8 W does not seem to be based on any actual physics. Check the units! I can't tell if you did $P=F\cdot m$ or $P=\frac{F}{m}$, but the result is either the nonsensical quantity of joule-kilogram per meter, or acceleration respectively.

A correct calculation based on keeping something aloft by propelling air downwards would be as follows. To keep something aloft, you need to expel mass downwards at a certain speed. The force to keep the object aloft is $$F=m_{object}g$$ The force generated by downwards momentum transfer is $$F=\dot{m}v$$ with $\dot{m}$ indicating mass flow (kilogram per second) of the air (not the mass of the object). The energy flow (power) required to  impart this momentum on the airflow is $$ P=\frac{1}{2}\dot{m}v^2$$ Here we can draw an important conclusion. The power requirement is arbitrarily small, by increasing the mass flow and decreasing the downwards velocity. Immediately, you can see why helicopters have big rotors and airplane wings are so large: they want to affect as much air mass as possible for increased efficiency. Even flying faster increases lift efficiency (reduced induced drag) by affecting more air per unit of time. Of course, at some point other sources of drag will dominate.



The above calculations assume that force is purely generated by creating a downwards mass flow. This is not exact reality. For example, put your aircraft on the ground, and it does not sink through it even though no mass flow is created. When flying close to the ground, some of the airflow downwards creates a pressure due to hitting the ground below, which helps you keep aloft as well (this is called the ground effect). Other than that, viscosity plays a small role by generating a force opposite the downwards air movement (although viscosity is required for lift generation with an airfoil). However, to answer the main question: equating lift by how much air is moved is a very good approximation.



Let's finally address your idea of using a Bell nozzle. This is a nozzle that is used on supersonic propellants (the 'throat' of the nozzle marks the transition from subsonic to supersonic), and is used to increase the speed as much as possible. This is very inefficient in terms of energy, but since rockets need to carry all the propellant mass (whereas an airplane gets 'free' mass flow by travelling through air), and need extra propellant to carry that propellant up, speed wins instead of mass, and rocket engines are optimised for nozzle velocity.