Thailand made 94 for eight and then Nattaya grabbed four wickets for just seven runs as Malaysia was bowled out for 63 in 16.2 overs.
Extras (25) contributed more to Thailand’s total than any batter: Nattakan Chantam top scored with 19 and Nattaya scored a useful 14.
Malaysia didn’t recover from two early run outs and also lost its last four wickets for just one runs with Nattaya claiming two of them.
Thailand will meet China in the last group match on Wednesday, with the winner to play Bangladesh in semis.
“We don’t have specific plan (for China) right now, but we are ready for it,” Nattaya said.
In the day’s other match, Nepal removed seven Hong Kong batters for just one run in its convincing seven-wicket victory.
Hong Kong was well placed at 71-2 — thanks to Wong Connie Aryan’s 47 off 55 balls — but ended its 20 overs at 72-9 after a series of bizarre run outs.
Wong and Yasmin Daswani (10) added 44 runs for the third wicket before six batters were run out and Mariko Tabitha was bowled by Nary Thapa without scoring.
Nepal cruised to victory for the loss of just three wickets in 15.2 overs, with Nary top scoring with 27 and Neera Rajpopadhay unbeaten on 12.
Nepal will take on Japan on Wednesday and the winner will meet favorites Pakistan in the other semifinals.
