A government-guaranteed basic income (economist.com)

I would predict that such inflation would be short lived. On a basic income, the majority of money would be spent on mostly basic products, with the occasional, but rare luxury. This would suggest a lot more dollars chasing few goods, but not the type of goods where the marginal cost of production is high. Any initial inflation would therefore be eroded by increased commoditification of basic products.

I don't think this impact would be large at all for industries that approximate perfect competition like raw food. Price of such goods should approximate marginal cost. Marginal cost would only increase if workers in these industries could now demand higher wages than before, which doesn't seem likely to me unless the basic income is very high. Do you expect their wages to rise? If anything, I would hope basic income would go side-by-side with abolishing minimum wage, which could decrease the price of such goods.

You may very well be right for some other goods, but food is a good example where production can scale up but is essentially a no-margin industry. And it's a very important example in the context of eliminating poverty.

Of course, the only way to prove it is to try it out and see :)

A more optimistic prediction is that a UBI would encourage the development of more low-income housing.