Besides Nepal, India, Pakistan and Sri Lanka advanced to the quarter-finals.
Nepal and India took the top two spots in Group D, while Pakistan and Sri Lanka advanced from Group B.
Opting to bat, Ireland got all out for a mere 131 for nine and then Nepal, which had stunned New Zealand in their opening match, coasted home in the 26th over with Yogendra Karki making 61.
In Sylhet, Sri Lanka survived a tense run-chase by Afghanistan before clinching win and a place in the quarters.
Skipper Charith Asalanka top-scored with 71 in Sri Lanka's modest 184 all out, but Afghanistan were bowled out for 151 despite opener Karim Janat's 40 and Waheedullah Shafaq's 47.
Kamindu Mendis, who possesses a rare talent of bowling both right-arm off-spin and left-arm orthodox spin, claimed three wickets for 36 runs.
Meanwhile, Pakistan scored a seven-wicket win over Canada after bowling out the unfancied rival for 178.
The Pakistanis surpassed the target in the 41st over with opener Zeeshan Malik scoring an unbeaten 89 and Saif Badar 44. Zeeshan was later declared player of the tournament.
Brief scores:
Group D: Nepal beat Ireland by eight wickets in Fatullah
Ireland: 131 for 9, 50 overs (Harry Tector 30 not out; Sandeep Lamichhane 5/27, Dipendra Airee 2/18).
Nepal: 132 for 2, 25.3 overs (Yogendra Karki 61, Aarif Sheikh 31 not out).
Group B: Sri Lanka beat Afghanistan by 33 runs in Sylhet
Sri Lanka: 184 all out, 48.1 overs (Charith Asalanka 71; Shamsurrahman Wali 3/19, Karim Janat 2/37, Zahir Khan 2/36).
Pakistan beat Canada by seven wickets in Sylhet
Canada: 178 all out, 48.3 overs (Bhavindu Adhihetty 51, Abraash Khan 44; Hasan Khan 3/36, Shadab Khan 2/44).
Pakistan: 180 for 3, 40.5 overs (Zeeshan Malik 89 not out, Saif Badar 44).
