effect: If this face-up card would be destroyed, you can destroy 1 face-up Plant-Type monster you control instead.

Card rulings: Nettles' effect does not target.
If "Nettles" is attacked while face-down, its effect cannot be applied when it is destroyed by battle.
If "Nettles" is attacked by "Drillroid" while in face-down Defense Position, "Nettle's" effect cannot be applied.
Ok this monsters effects is not one of the best effects known in the game but it is still a interesting cards because of 2 things
source: http://www.netrep.net/

1- it is a plant
2- it is a level 2
3- most importantly it is a tuner

being a plant means that it is a target for cards like:

-Miracle fertilizer: ce per turn, you can select 1 Plant-Type monster from your Graveyard and Special Summon it. You cannot Normal Summon or Set the turn you Special Summon a monster with this effect. If a monster Special Summoned by this effect is removed from the field, destroy this card.

-gigaplant (very important): This card is treated as a Normal Monster while face-up on the field or in the Graveyard. While this card is face-up on the field, you can Normal Summon it to have it be treated as an Effect Monster with this effect:
● Once per turn, you can Special Summon 1 Insect-Type or Plant-Type monster from your hand or Graveyard.
-mark of the rose: Remove from play 1 Plant-Type monster from your Graveyard and equip this card to a monster your opponent controls. Gain control of the equipped monster. During your End Phase, give control of the equipped monster to your
opponent. During your Standby Phase, gain control of the equipped monster.
Lonefire blossom : Once per turn, you can Tribute 1 face-up Plant-Type monster to Special Summon 1 Plant-Type monster from your Deck.

The world tree:
Each time a Plant-Type monster(s) on the field is destroyed, place 1 Flower Counter on this card. You can remove Flower Counters to activate this card's effects. ● Remove 1: Target face-up Plant-Type monster gains 400 ATK and DEF until the End Phase. ● Remove 2: Destroy 1 card on the field. ● Remove 3: Select 1 Plant-Type monster from your Graveyard and Special Summon it.

Well those are the most important once anyway

Being a lv 2 is great for this card cuz this means that togeder with gigplant it can become a lv 8 synchro monster and most likely
Black Brutdrago: 1 Tuner + 1 or more non-Tuner Gemini monsters
Once per turn, you can send 1 Gemini monster from your hand to the Graveyard to select and destroy 1 Spell or Trap Card your opponent controls. When this card is destroyed and sent to the Graveyard, you can select 1 Gemini monster in your Graveyard and Special Summon it. The Special Summoned Gemini monster is treated as an Effect Monster, and gains its effect.

And being a lv 2 tuner can be used to summon a goyo or brionac easy with a lv 4 monsters.

Being a lv 2 plant monster also allows good use of
super solar nutrient: Tribute 1 Level 2 or lower Plant-Type monster. Special Summon 1 Plant-Type monster whose Level is equal to or lower than the Tributed monster's Level +3 from your hand or Deck. When this card is removed from the field, destroy that monster. When that monster is removed from the field, destroy this card.

With this you can easy summon lonefire blossom and in turn tribute him for a gigaplant or a tytannial,princess of camellias.
Note: You can also first summon another lonefire blossom to fill you graveyard.

When talking about a combo with nettles there is one that tops all.

This can be easily Summoned in a Plant deck with "Gigaplant" and "Nettles". When this is destroyed, you can Summon "Gigaplant" back, use its effect to Summon "Nettles" and get another copy of this card.
(talking about Black Brutdrago)
source of this http://yugioh.wikia.com/wiki/Card_Tips:Black_Brutdrago