Annoyed and stuck

Ok 1st off, back story. I work from home. I have a 2 year old who has major social anxiety. My mother in law is my daytime nanny when I'm working. When I say major I mean major so finding a new nanny isn't in our cards. 
Ok now problem. My mother in law is beyond addicted to a Cell phone game. She plays this game pretty much non stop and even admits to staying up til 4 or 5 am. Normally wouldn't give two shits about it but as I said above she is my nanny. Now my husband and I have done every thing we can to lessen the need. He has a day off in the week and I do as well. Instead of us coordinating them together we have separate days so to avoid the need of his mom. Also she is only watching her from 9 am til 1:30pm. So the stretch of time isn't vast or over strenuous. Well she does nothing but play that damn game. I mean she doesn't change her diapers or get her food. Won't change her into daytime clothes.  Since my daughter isn't a touch screen tablet she doesn't interact with her. If she was anyone else I would have ripped them up one way down the other and fired them. Instead we walk on eggshells cause she is also full on menopausal. 
My job is going to be laying people off and it's to the point that I'm almost hoping to get laid off so we wouldn't need her anymore. We are already planning to move closer to my parents after my two oldest boys graduate. I have changed my wiFi password but then she uses her own data as now she has unlimited data😐. I use to play that stupid game but I realized very early on how overly time consuming it was. It was way worse than world of Warcraft cause you can take it everywhere with you. 
Anyone have any advice on how to 1. Talk to your mother in law about a huge flaw or issue they are causing?
2. Do it gingerly as to not unleash the menopause beast( she takes nothing for it not even natural stuff)
3. Do all of this while keeping harmony as we are unfortunately in need of her since she is the only person my daughter will allow to watch her. 
Also I will add that we don't even ask her to watch her but rarely outside of the 3 days for a few hours cause she wouldn't baby proof her house including very steep stairs. Would leave her unattended upstairs when she could have tried to go down them and fallen. My husband is depressed cause his brother and sisters kids have always been well cared for by his mom and she does so much for them but does so little for ours. My daughter isn't a little snot or brat but even if she was that's no reason to be so self absorbed you can't even spend time with your grand daughter which my parents would kill for that opportunity.  
Has anyone had a positive outcome of comfronting an inlaw? My husband is shy from conflict anyway and on top of that its his mom. Anyway looking for useful advice not hate and angry comments. Thanks in advance for those who want to help.