土豆片 covers two senses depending on context: hand-cut potato slices in home cooking (like 醋溜土豆片 sweet-and-sour shredded potato), or packaged potato chips/crisps. For the snack sense, 薯片 (shǔpiàn) is more common in mainland marketing.
memory
土豆 = 'earth bean' = potato (a Northern Chinese term; Southerners may say 马铃薯 mǎlíngshǔ). Add 片 (piàn 'slice') and you have potato slices.
