Moutai moved to I think Continental Centre? The joint that took over Moutai still serves tan-tan noodles but it sucks like Levitron said. The original Moutai that moved serves it the same way they used to always make it.
There's a joint inside Crystal Mall at the food court. The place is the furthest one to the south of the food court - some kind of Shanghainese restaurant. It's not as cheap as Moutai for $2
but not as good neither but it was the second best I was able to find to Moutai.