B2B platform for speciality chemicals Covvalent, founded by Harvard and IIT alumni Sandeep Singh and Arush Dhawan, has secured $4.3 million in a seed funding round led by Nexus Venture Partners. The round also saw participation from angel investors including Zetwerk Co-founder Vishal Chaudhary, Livspace Co-founder Ramakant Sharma and BlackBuck Co-founder Rajesh Yabaji, among others.