Based on the level of respect or formality, you can say "Hello. Nice to meet you!" in Korean in 3 ways:

• Informal: anyeong? mannaseo bangaweo! (안녕? 만나서 반가워!)
• Formal: anyeong haseyo? mannaseo bangawayo! (안녕하세요? 만나서 반가워요!)
• Very Formal: anyeong hasipnigga? mannaseo bangapseupnida! (안녕 하십니까? 만나서 반갑습니다), anyeong hasipnigga? manna-boipge doieo bangapseupnida! (안녕하십니까? 만나뵙게 되어 반갑습니다!)

- hello: anyeong (안녕)
- nice to meet: manaseo jotta (만나서 좋다)
- nice to meet you: manaseo bangapda (만나서 반갑다), neo-reul manaseo bangapda (너를 만나서 반갑다)
- you (objective): neo-reul (너를), dangsin-eul (당신을)

Please refer to How to pronounce Korean Alphabet for the English pronunciation in this answer.