Ok as others have said ground rules.I aslo think compromise is key. Grandparents are excited too but husband should back you. Agree these rules with him first, get him on board then present a united front.
The no kissing baby, there are articles recently which can enforce the reasoning behind this, babies can die from kisses. Find that article, use that as the reason, backed by science that no kissing on the face, kiss the clothed belly, the clothed feet (compromise os key).
Somome mentioned setting boundaries around activities, youve just goven birth, dont host, dont cater, dont move to get people food or drink; simple - someone asks for something - I've just given birth, husband will get it, he jumps up to do whatever task.
Dont have them over all day, every day, set times and boundaries.
Someone mentioned putting baby in a sling, I like this idea but don't use it as a weapon.
Basically you have to recognise you have a problem with MIL, but she has a right to be excited, it should be a joyous time for you all so you need to get hubby on board with riles and act as a united front or else you'll feel alone and defeated and that's the root of your issue. You're vulnerable after a birth; he needs to step up and not be a mummy's boy, but you need to not be a controlling nasty vindictive cow as a result.