They won't die, but it's not ideal. Chicks that age are growing quickly, so they will show problems faster than an adult chicken would.
The biggest problem I see is lack of protein, so I would try to give them some protein to go with it.
Things like cat food, puppy food, or fish food might work (check the label: you probably want at least 20% protein if you are giving it alongside scratch. Some kitten foods and fish foods have 40% protein or more, and that is great for a supplement in this situation.)
Human foods like egg, meat, and fish are great sources of protein.
Beans, lentils, and similar things can be reasonable protein sources, but they need to be cooked (not raw/dry.) If they are moist in a can, they have already been cooked and are fine.
Bugs and worms are fine too, although it takes a large number to make much difference.
It might be good to also offer greens, fruits, and vegetables. Chicks can be picky about what they eat, so it's hard to know what will work and what will not.
Do make sure they have grit available, so their gizzards can grind up the grains (scratch) and the other things they eat.