252 Atk Life Orb Bisharp Iron Head vs. 252 HP / 252+ Def Chesnaught: 105-125 (27.6 - 32.8%) -- 75.3% chance to 4HKO after Leftovers recovery
0 Atk Chesnaught Drain Punch vs. 0 HP / 4 Def Bisharp: 340-408 (125.4 - 150.5%) -- guaranteed OHKO
0 SpA Slowbro Psyshock vs. 252 HP / 252+ Def Chesnaught: 110-132 (28.9 - 34.7%) -- 99.6% chance to 4HKO after Leftovers recovery
0 Atk Chesnaught Wood Hammer vs. 252 HP / 232+ Def Slowbro: 188-224 (47.7 - 56.8%) -- 38.7% chance to 2HKO after Leftovers recovery
252 Atk Life Orb Weavile Icicle Crash vs. 252 HP / 252+ Def Chesnaught: 218-257 (57.3 - 67.6%) -- guaranteed 2HKO after Leftovers recovery
0 Atk Chesnaught Drain Punch vs. 0 HP / 4 Def Weavile: 484-576 (172.2 - 204.9%) -- guaranteed OHKO
It may not be able to switch in directly on Weavile, but once inside it can demolish the frigid weasel with extreme ease.
(Calm Mind) 0 SpA Manaphy Scald vs. 252 HP / 4 SpD Chesnaught: 54-64 (14.2 - 16.8%) -- possible 9HKO after Leftovers recovery
(Calm Mind) 0 SpA Manaphy Scald vs. 252 HP / 4 SpD Chesnaught in Rain: 81-96 (21.3 - 25.2%) -- possible 5HKO after Leftovers recovery
0 Atk Chesnaught Wood Hammer vs. 240 HP / 252+ Def Manaphy: 198-234 (49.3 - 58.3%) -- 60.2% chance to 2HKO after Leftovers recovery
(Tail Glow+Rain Dance) +3 252 SpA Manaphy Scald vs. 252 HP / 4 SpD Chesnaught: 171-202 (45 - 53.1%) -- 0.4% chance to 2HKO after Leftovers recovery
(Tail Glow+Rain Dance) +3 252 SpA Manaphy Scald vs. 252 HP / 4 SpD Chesnaught in Rain: 258-303 (67.8 - 79.7%) -- guaranteed 2HKO after Leftovers recovery
0 Atk Chesnaught Wood Hammer vs. 96 HP / 0 Def Manaphy: 272-324 (74.5 - 88.7%) -- guaranteed 2HKO after Leftovers recovery
Chesnaught can handle CM Manaphy and RainGlow Manaphy relatively well, as long as Manaphy lacks Ice Beam/Psychic and Chesnaught keeps applying pressure on Manaphy.
(ScarfTar) 252 Atk Tyranitar Superpower vs. 252 HP / 252+ Def Chesnaught: 85-100 (22.3 - 26.3%) -- 15.8% chance to 4HKO after sandstorm damage and Leftovers recovery
0 Atk Chesnaught Drain Punch vs. 0 HP / 4 Def Tyranitar: 316-376 (92.6 - 110.2%) -- 50% chance to OHKO
(Support) 0 SpA Tyranitar Ice Beam vs. 252 HP / 4 SpD Chesnaught: 158-186 (41.5 - 48.9%) -- guaranteed 3HKO after sandstorm damage and Leftovers recovery
0 Atk Chesnaught Drain Punch vs. 248 HP / 252+ Def Tyranitar: 232-280 (57.5 - 69.4%) -- guaranteed 2HKO after Leftovers recovery
252 Atk Mega Tyranitar Ice Punch vs. 252 HP / 252+ Def Chesnaught: 124-146 (32.6 - 38.4%) -- 97.9% chance to 3HKO after sandstorm damage and Leftovers recovery
+1 252 Atk Mega Tyranitar Ice Punch vs. 252 HP / 252+ Def Chesnaught: 182-216 (47.8 - 56.8%) -- 89.5% chance to 2HKO after sandstorm damage and Leftovers recovery
0 Atk Chesnaught Drain Punch vs. 0 HP / 4 Def Mega Tyranitar: 240-288 (70.3 - 84.4%) -- guaranteed 2HKO
252 Atk Mega Lopunny High Jump Kick vs. 252 HP / 252+ Def Chesnaught: 138-163 (36.3 - 42.8%) -- 97.2% chance to 3HKO after Leftovers recovery
0 Atk Chesnaught Drain Punch vs. 0 HP / 4 Def Mega Lopunny: 182-216 (67.1 - 79.7%) -- guaranteed 2HKO
252+ Atk Mold Breaker Mega Gyarados Ice Fang vs. 252 HP / 252+ Def Chesnaught: 112-134 (29.4 - 35.2%) -- 100% chance to 4HKO after Leftovers recovery
+1 252+ Atk Mold Breaker Mega Gyarados Ice Fang vs. 252 HP / 252+ Def Chesnaught: 168-198 (44.2 - 52.1%) -- guaranteed 3HKO after Leftovers recovery
0 Atk Chesnaught Wood Hammer vs. 0 HP / 4 Def Mega Gyarados: 254-300 (76.7 - 90.6%) -- guaranteed 2HKO
0 Atk Chesnaught Drain Punch vs. 0 HP / 4 Def Mega Gyarados: 158-188 (47.7 - 56.7%) -- 87.5% chance to 2HKO
Beware of pre-Mega's Intimidate!
252+ Atk Strong Jaw Mega Sharpedo Ice Fang vs. 252 HP / 252+ Def Chesnaught: 154-182 (40.5 - 47.8%) -- guaranteed 3HKO after Leftovers recovery
0 Atk Chesnaught Wood Hammer vs. 0 HP / 4 Def Mega Sharpedo: 366-432 (130.2 - 153.7%) -- guaranteed OHKO
0 Atk Chesnaught Drain Punch vs. 0 HP / 4 Def Mega Sharpedo: 228-270 (81.1 - 96%) -- guaranteed 2HKO