Like the answer to so many legal questions, the answer to this question depends on your specific circumstances. If you receive Supplemental Security Income (SSI) over $30 per month (at the time of this writing) then the answer is yes, the Social Security Administration (SSA) will lower your SSI payment to $30 per month. Social Security Disability Insurance (SSDI), or Social Security Retirement, however, should never be lowered in this fashion. As long as Medicare or some other insurer is paying your nursing home bill you are entitled to your SSDI/SS Retirement check. The same goes for the unfortunate situation in which you are paying your own nursing home bills.
In Maryland, if Medicaid starts paying your nursing home bill, however, you will start to be responsible for a "cost of care." Your "cost of care" is most of your income if you're single but not paid to the government. You owe that money to the nursing home, and for-profit nursing homes are generally very aggressive in relation to collecting "cost of care." You should not lose your Medicaid if you don't pay "cost of care" but the nursing home bill office will be not-so-happy campers. The nursing home may try to kick you out of the facility by bullying you/your family or even try to get you evicted!
On the other hand, in a situation where you are on Medicaid and have a spouse in the community, there is a spousal allowance if your spouse is dependent on your income to pay living expenses. The "cost of care" is reduced and the Medicaid payment is increased to account for those living expenses. But a spouse with a large income will not be entitled to a spousal allowance.
Disclaimer: This post is for informational purposes only and not intended to be legal advice.