#JavaScript (ES6), 33 28 bytes
n=>eval(1+("*"+n).repeat(n))
##Try It Late night golfing on my phone again; if the below doesn't work, feel free to fix it.
f=
n=>eval(1+("*"+n).repeat(n))
o.innerText=f(i.value=3)
i.oninput=_=>o.innerText=f(+i.value)<input id=i type=number><pre id=o>##33 byte solution
n=>eval(Array(n).fill(n).join*)