我敢素颜小白衫帆布鞋溜达
[wŏ găn sù yán xiăo bái shān fān bù xié liū dá]
In this phrase, '溜达' means casually strolling or walking around leisurely. Thus the entire nickname '我敢素颜小白衫帆布鞋溜达' roughly implies the courage to wander around without any particular preparations: not bothering about makeup (with bareface), dressed simply (white shirt and canvas shoes).