1. If there is a registered LL agreement with them then on its basis they can apply for license of Nursing Home.
2. However you can seek injunction in your eviction suit so that the court may restrain them from starting any business venture if they same has not been mentioned in the LL agreement.
3. You can inform the local licencing authority as well about the injunction order , once passed so they also intervene.
4. So engage an good advocate and ask for injunction at all costs.